<PAGE>

                                                                   EXHIBIT 10.1


                             STOCK OPTION AGREEMENT

         THIS STOCK OPTION AGREEMENT (this "AGREEMENT") is made and entered into
as of June 20, 2000, among Commerce One, Inc., a Delaware corporation
("PARENT"), and Appnet, Inc., a Delaware corporation (the "COMPANY").
Capitalized terms used but not otherwise defined herein will have the meanings
ascribed to them in the Reorganization Agreement (as defined below).

                                    RECITALS

         A. The Company, Merger Sub (as defined below) and Parent have entered
into an Agreement and Plan of Merger and Reorganization, dated the date hereof
(the "REORGANIZATION AGREEMENT") which provides for the merger (the "MERGER") of
a wholly-owned subsidiary of Parent ("MERGER SUB") with and into the Company.
Pursuant to the Merger, all outstanding capital stock of the Company will be
converted into the right to receive Common Stock of Parent.

         B. As a condition to Parent's willingness to enter into the
Reorganization Agreement, Parent has requested that Company agree, and Company
has so agreed, to grant to Parent an option to acquire shares of Company's
Common Stock, (together, the "COMPANY SHARES"), upon the terms and subject to
the conditions set forth herein.

         NOW, THEREFORE, in consideration of the foregoing and of the mutual
covenants and agreements set forth herein and in the Reorganization Agreement
and for other good and valuable consideration, the receipt and adequacy of which
are hereby acknowledged, the parties hereto agree as follows:

         1. GRANT OF OPTION. The Company hereby grants to Parent an irrevocable
option (the "OPTION") to acquire up to a number of Company Shares equal to 19.9%
of the issued and outstanding shares as of the first date, if any, upon which an
Exercise Event (as defined in Section 2(a) below) occurs (the "OPTION SHARES"),
in the manner set forth below by paying cash at a price of $40.35 per share (the
"EXERCISE PRICE").

         2.       EXERCISE OF OPTION; MAXIMUM PROCEEDS.

                  (a) The Option may be exercised by Parent, in whole or in
part, at any time or from time to time if the Reorganization Agreement is
terminated pursuant to Section 7.1(b), 7.1(d), 7.1(g) or 7.1(h) thereof and an
event causing the Termination Fee to become payable pursuant to Section 7.3(b)
of the Reorganization Agreement occurs (any of the events being referred to
herein as an "EXERCISE EVENT"). In the event Parent wishes to exercise the
Option, Parent will deliver to the Company a written notice (each an "EXERCISE
NOTICE") specifying the total number of Option Shares it wishes to acquire. Each
closing of a purchase of Option Shares (a "CLOSING") will occur on a date and at
a time prior to the termination of the Option designated by Parent in an
Exercise Notice delivered at least two business days prior to the date of such
Closing, which Closing will be held at the principal offices of the Company.

                  (b) The Option will terminate upon the earliest of (i) the
Effective Time, (ii) twelve (12) months following the date on which the
Reorganization Agreement is terminated


<PAGE>

pursuant to Section 7.1(b), 7.1(d) or 7.1(g) thereof, if no event causing the
Termination Fee to become payable pursuant to Section 7.3(b)(ii) of the
Reorganization Agreement has occurred, (iii) twelve (12) months following the
date on which the Reorganization Agreement is terminated pursuant to Section
7.1(h) thereof, (iv) in the event the Reorganization Agreement has been
terminated pursuant to Section 7.1(b), 7.1(d) or 7.1(g) thereof and the
Termination Fee became payable pursuant to Section 7.3(b)(ii) thereof, twelve
(12) months after payment of the Termination Fee; and (v) the date on which the
Reorganization Agreement is terminated for any other reason if neither a
Triggering Event nor the announcement of an Acquisition Proposal by a third
party occurred on or prior to the date of such termination; PROVIDED, HOWEVER,
that if the Option cannot be exercised by reason of any applicable government
order or because the waiting period related to the issuance of the Option Shares
under the HSR Act will not have expired or been terminated, then the Option will
not terminate until the tenth business day after such impediment to exercise
will have been removed or will have become final and not subject to appeal.

         3. CONDITIONS TO CLOSING. The obligation of Company to issue Option
Shares to Parent hereunder is subject to the conditions that (A) any waiting
period under the HSR Act applicable to the issuance of the Option Shares
hereunder will have expired or been terminated; (B) all material consents,
approvals, orders or authorizations of, or registrations, declarations or
filings with, any Federal, state or local administrative agency or commission or
other Federal state or local governmental authority or instrumentality, if any,
required in connection with the issuance of the Option Shares hereunder will
have been obtained or made, as the case may be; and (C) no preliminary or
permanent injunction or other order by any court of competent jurisdiction
prohibiting or otherwise restraining such issuance will be in effect. It is
understood and agreed that at any time during which the Option is exercisable,
the parties will use their respective best efforts to satisfy all conditions to
Closing, so that a Closing may take place as promptly as practicable.

         4. CLOSING. At any Closing, (A) the Company will deliver to Parent a
single certificate in definitive form representing the number of Company Shares
designated by Parent in its Exercise Notice, such certificate to be registered
in the name of Parent and to bear the legend set forth in Section 9 hereof,
against delivery of (B) payment by Parent to the Company of the aggregate
purchase price for the Company Shares so designated and being purchased by
delivery of a certified check or bank check.

         5. REPRESENTATIONS AND WARRANTIES OF THE COMPANY. Company represents
and warrants to Parent that (A) Company is a corporation duly organized, validly
existing and in good standing under the laws of the State of Delaware and has
the corporate power and authority to enter into this Agreement and to carry out
its obligations hereunder; (B) the execution and delivery of this Agreement by
the Company and consummation by the Company of the transactions contemplated
hereby have been duly authorized by all necessary corporate action on the part
of the Company and no other corporate proceedings on the part of the Company are
necessary to authorize this Agreement or any of the transactions contemplated
hereby; (C) this Agreement has been duly executed and delivered by the Company
and constitutes a legal, valid and binding obligation of the Company and,
assuming this Agreement constitutes a legal, valid and binding obligation of
Parent, is enforceable against the Company in accordance with its terms; (D)
except for any filings required under the HSR Act, the Company has taken all
necessary corporate and other action to authorize and reserve for issuance and
to permit it to issue upon exercise of the Option, and at all times from the


                                      -2-
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date hereof until the termination of the Option will have reserved for issuance,
a sufficient number of unissued Company Shares for Parent to exercise the Option
in full and will take all necessary corporate or other action to authorize and
reserve for issuance all additional Company Shares or other securities which may
be issuable pursuant to Section 8(a) upon exercise of the Option, all of which,
upon their issuance and delivery in accordance with the terms of this Agreement,
will be validly issued, fully paid and nonassessable; (E) upon delivery of the
Company Shares and any other securities to Parent upon exercise of the Option,
Parent will acquire such Company Shares or other securities free and clear of
all material claims, liens, charges, encumbrances and security interests of any
kind or nature whatsoever, excluding those imposed by Parent; (F) the execution
and delivery of this Agreement by the Company do not, and the performance of
this Agreement by the Company will not, (i) conflict with or violate the
Certificate of Incorporation or Bylaws or equivalent organizational documents of
the Company or any of its subsidiaries, (ii) conflict with or violate any law,
rule, regulation, order, judgment or decree applicable to the Company or any of
its subsidiaries or by which its or any of their respective properties is bound
or affected or (iii) result in any breach of or constitute a default (or an
event that with notice or lapse of time or both would become a default) under,
or impair the Company's or any of its subsidiaries' rights or alter the rights
or obligations of any third party under, or give to others any rights of
termination, amendment, acceleration or cancellation of, or result in the
creation of a lien or encumbrance on any of the properties or assets of the
Company or any of its subsidiaries pursuant to, any material note, bond,
mortgage, indenture, contract, agreement, lease, license, permit, franchise or
other instrument or obligation to which the Company or any of its subsidiaries
is a party or by which the Company or any of its subsidiaries or its or any of
their respective properties are bound or affected, except in the case of clause
(ii) or (iii) above, for any such conflicts, breaches, violations, defaults or
other occurrences that would not, individually or in the aggregate, reasonably
be expected to have a Material Adverse Effect; and (G) the execution and
delivery of this Agreement by the Company does not, and the performance of this
Agreement by the Company will not, require any consent, approval, authorization
or permit of, or filing with, or notification to, any Governmental Entity except
compliance with applicable requirements of the Securities Act, the Exchange Act,
Blue Sky Laws, the HSR Act or where the failure to obtain such approvals, or to
make such filings or notifications, could not, individually or in the aggregate,
reasonably be expected to have a Material Adverse Effect.

         6.       CERTAIN RIGHTS.

                  (a) PARENT PUT. At the request of and upon notice by Parent
(the "PUT NOTICE"), at any time during the period during which the Option is
exercisable pursuant to Section 2 (the "PURCHASE PERIOD"), the Company (or any
successor entity thereof) will purchase from Parent the Option, to the extent
not previously exercised, at the price set forth in subparagraph (i) below (as
limited by subparagraph (iii) below), and the Option Shares, if any, acquired by
Parent pursuant thereto, at the price set forth in subparagraph (ii) below (as
limited by subparagraph (iii) below):

                               (i)   The difference between the "MARKET/TENDER
OFFER PRICE" for the Company Shares as of the date Parent gives notice of its
intent to exercise its rights under this Section 6(a) (defined as the higher of
(A) the highest price per share offered as of such date pursuant to any
Acquisition Proposal which was made prior to such date and (B) the highest
closing sale price of Company Shares then on the Nasdaq National Market during
the 20 trading days ending on the


                                      -3-
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trading day immediately preceding such date) and the Exercise Price, multiplied
by the number of Company Shares purchasable pursuant to the Option, but only if
the Market/Tender Offer Price is greater than the Exercise Price. For purposes
of determining the highest price offered pursuant to any Acquisition Proposal
which involves consideration other than cash, the value of such consideration
will be equal to the higher of (x) if securities of the same class of the
proponent as such consideration are traded on any national securities exchange
or by any registered securities association, a value based on the closing sale
price or asked price for such securities on their principal trading market on
such date and (y) the value ascribed to such consideration by the proponent of
such Acquisition Proposal, or if no such value is ascribed, a value determined
in good faith by the Board of Directors of the Company.

                               (ii)  The Exercise Price paid by Parent for
Company Shares acquired pursuant to the Option PLUS the difference between the
Market/Tender Offer Price and such Exercise Price (but only if the Market/Tender
Offer Price is greater than the Exercise Price) multiplied by the number of
Company Shares so purchased.

                               (iii) Notwithstanding subparagraphs (i) and (ii)
above, pursuant to this Section 6 Company will not be required to pay Parent in
excess of an aggregate of (x) $54,375,000 PLUS (y) the Exercise Price paid by
Parent for Company Shares acquired pursuant to the Option MINUS (z) any amounts
paid to Parent by the Company pursuant to Section 7.3(b) of the Reorganization
Agreement.

                  (b) PAYMENT AND REDELIVERY OF OPTION OR SHARES. In the event
Parent exercises its rights under Section 6(a), the Company will, within five
business days after Parent delivers notice pursuant to Section 6(a), pay the
required amount to Parent in immediately available funds and Parent will
surrender to the Company the Option and the certificates evidencing the Company
Shares purchased by Parent pursuant thereto.

         7.       REGISTRATION RIGHTS.

                  (a) Following the termination of the Reorganization Agreement,
Parent (sometimes referred to herein as the "HOLDER") may by written notice (a
"REGISTRATION NOTICE") to the Company (the "REGISTRANT") request the Registrant
to register under the Securities Act all or any part of the shares acquired by
the Holder pursuant to this Agreement (such shares requested to be registered,
the "REGISTRABLE SECURITIES") in order to permit the sale or other disposition
of any or all shares of the Registrable Securities that have been acquired by or
are issuable to Holder upon exercise of the Option in accordance with the
intended method of sale or other disposition stated by Holder, including a
"shelf" registration statement under Rule 415 under the Securities Act or any
successor provision. Holder agrees to cause, and to cause any underwriters of
any sale or other disposition to cause, any sale or other disposition pursuant
to such registration statement to be effected on a widely distributed basis so
that upon consummation thereof no purchaser or transferee will own beneficially
more than 5.0% of the then-outstanding voting power of Registrant. Upon a
request for registration, the Registrant will have the option exercisable by
written notice delivered to the Holder within ten business days after the
receipt of the Registration Notice, irrevocably to agree to purchase all or any
part of the Registrable Securities for cash at a price (the "OPTION PRICE" equal
to the product of (i) the number of Registrable Securities so purchased and (ii)
the per share average


                                      -4-
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of the closing sale prices of the Registrant's Common Stock on the Nasdaq
National Market for the ten trading days immediately preceding the date of the
Registration Notice. Any such purchase of Registrable Securities by the
Registrant hereunder will take place at a closing to be held at the principle
executive offices of the Registrant or its counsel at any reasonable date and
time designated by the Registrant in such notice within ten business days after
delivery of such notice. The payment for the shares to be purchased will be made
by delivery at the time of such closing of the Option Price in immediately
available funds.

                  (b) If the Registrant does not elect to exercise its option to
purchase pursuant to Section 7(a) with respect to all Registrable Securities,
the Registrant will use all reasonable efforts to effect, as promptly as
practicable, the registration under the Securities Act of the unpurchased
Registrable Securities requested to be registered in the Registration Notice and
to keep such registration statement effective for such period not in excess of
120 calendar days from the day such registration statement first becomes
effective as may be reasonably necessary to effect such sale or other
disposition; PROVIDED, HOWEVER, that the Holder will not be entitled to more
than an aggregate of three effective registration statements hereunder. The
obligations of Registrant hereunder to file a registration statement and to
maintain its effectiveness may be suspended for up to 120 calendar days in the
aggregate if the Board of Directors of Registrant shall have determined that the
filing of such registration statement or the maintenance of its effectiveness
would require premature disclosure of material nonpublic information that would
materially and adversely affect Registrant or otherwise interfere with or
adversely affect any pending or proposed offering of securities of Registrant or
any other material transaction involving Registrant. If consummation of the sale
of any Registrable Securities pursuant to a registration hereunder does not
occur within 120 days after the filing with the SEC of the initial registration
statement therefor, the provisions of this Section 7 will again be applicable to
any proposed registration. The Registrant will use all reasonable efforts to
cause any Registrable Securities registered pursuant to this Section 7 to be
qualified for sale under the securities or blue sky laws of such jurisdictions
as the Holder may reasonably request and will continue such registration or
qualification in effect in such jurisdictions; PROVIDED, HOWEVER, that the
Registrant will not be required to qualify to do business in, or consent to
general service of process in, any jurisdiction by reason of this provision. If
Registrant effects a registration under the Securities Act of Company Common
Stock for its own account or for any other stockholders of Registrant (other
than on Form S-4 or Form S-8, or any successor form), it will allow Holder the
right to participate in such registration by selling its Registrable Securities,
and such participation will not affect the obligation of Registrant to effect
demand registration statements for Holder under this Section 7; PROVIDED that,
if the managing underwriters of such offering advise Registrant in writing that
in their opinion the number of shares of Company Common Stock requested to be
included in such registration exceeds the number which can be sold in such
offering, Registrant will include the shares requested to be included therein by
Holder pro rata with the shares intended to be included therein by Registrant.

                  (c) The registration rights set forth in this Section 7 are
subject to the condition that the Holder will provide the Registrant with such
information with respect to the Holder's Registrable Securities, the plan for
distribution thereof, and such other information with respect to the Holder as,
in the reasonable judgment of counsel for the Registrant, is necessary to enable
the Registrant to include in a registration statement all facts required to be
disclosed with respect to a registration thereunder.


                                      -5-

<PAGE>

                  (d) A registration effected under this Section 7 will be
effected at the Registrant's expense, except for underwriting discounts and
commissions and the fees and expenses of counsel to the Holder, and the
Registrant will provide to the underwriters such documentation (including
certificates, opinions of counsel and "comfort" letters from auditors) as are
customary in connection with underwritten public offerings and as such
underwriters may reasonably require. In connection with any registration, the
Holder and the Registrant agree to enter into an underwriting agreement
reasonably acceptable to each such party, in form and substance customary for
transactions of this type with the underwriters participating in such offering.

                  (e)      INDEMNIFICATION.

                               (i)   The Registrant will indemnify the Holder,
each of its directors and officers and each person who controls the Holder
within the meaning of Section 15 of the Securities Act, and each underwriter of
the Registrant's securities, with respect to any registration, qualification or
compliance which has been effected pursuant to this Agreement, against all
expenses, claims, losses, damages or liabilities (or actions in respect
thereof), including any of the foregoing incurred in settlement of any
litigation, commenced or threatened, arising out of or based on any untrue
statement (or alleged untrue statement) of a material fact contained in any
registration statement, prospectus, offering circular or other document, or any
amendment or supplement thereto, incident to any such registration,
qualification or compliance, or based on any omission (or alleged omission) to
state therein a material fact required to be stated therein or necessary to make
the statements therein, in light of the circumstances in which they were made,
not misleading, or any violation by the Registrant of any rule or regulation
promulgated under the Securities Act applicable to the Registrant in connection
with any such registration, qualification or compliance, and the Registrant will
reimburse the Holder and, each of its directors and officers and each person who
controls the Holder within the meaning of Section 15 of the Securities Act, and
each underwriter for any legal and any other expenses reasonably incurred in
connection with investigating, preparing or defending any such claim, loss,
damage, liability or action; PROVIDED, that the Registrant will not be liable in
any such case to the extent that any such claim, loss, damage, liability or
expense arises out of or is based on any untrue statement or omission or alleged
untrue statement or omission, made in reliance upon and in conformity with
written information furnished to the Registrant by such Holder or director or
officer or controlling person or underwriter seeking indemnification.

                               (ii)  The Holder will indemnify the Registrant,
each of its directors and officers and each underwriter of the Registrant's
securities covered by such registration statement and each person who controls
the Registrant within the meaning of Section 15 of the Securities Act, against
all expenses, claims, losses, damages and liabilities (or actions in respect
thereof), including any of the foregoing incurred in settlement of any
litigation, commenced or threatened, arising out of or based on any untrue
statement (or alleged untrue statement) of a material fact contained in any such
registration statement, prospectus, offering circular or other document, or any
omission (or alleged omission) to state therein a material fact required to be
stated therein or necessary to make the statements therein not misleading, or
any violation by the Holder of any rule or regulation promulgated under the
Securities Act applicable to the Holder in connection with any such
registration, qualification or compliance, and will reimburse the Registrant,
such directors, officers or control persons or underwriters for any legal or any
other expenses reasonably incurred in connection with investigating, preparing
or defending any such claim, loss, damage, liability or


                                      -6-
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action, in each case to the extent, but only to the extent, that such untrue
statement (or alleged untrue statement) or omission (or alleged omission) is
made in such registration statement, prospectus, offering circular or other
document in reliance upon and in conformity with written information furnished
to the Registrant by the Holder for use therein; PROVIDED, that in no event will
any indemnity under this Section 7(e) exceed the net proceeds of the offering
received by the Holder.

                               (iii) Each party entitled to indemnification
under this Section 7(e) (the "INDEMNIFIED PARTY") will give notice to the party
required to provide indemnification (the "INDEMNIFYING PARTY") promptly after
such Indemnified Party has actual knowledge of any claim as to which indemnity
may be sought, and will permit the Indemnifying Party to assume the defense of
any such claim or any litigation resulting therefrom, PROVIDED, that counsel for
the Indemnifying Party, who will conduct the defense of such claim or
litigation, will be approved by the Indemnified Party (whose approval will not
unreasonably be withheld), and the Indemnified Party may participate in such
defense at such party's expense; PROVIDED, HOWEVER, that the Indemnifying Party
will pay such expense if representation of the Indemnified Party by counsel
retained by the Indemnifying Party would be inappropriate due to actual or
potential differing interests between the Indemnified Party and any other party
represented by such counsel in such proceeding, and PROVIDED FURTHER, HOWEVER,
that the failure of any Indemnified Party to give notice as provided herein will
not relieve the Indemnifying Party of its obligations under this Section 7(e)
unless the failure to give such notice is materially prejudicial to an
Indemnifying Party's ability to defend such action. No Indemnifying Party, in
the defense of any such claim or litigation will, except with the consent of
each Indemnified Party, consent to entry of any judgment or enter into any
settlement which does not include as an unconditional term thereof the giving by
the claimant or plaintiff to such Indemnified Party of a release from all
liability in respect to such claim or litigation. No Indemnifying Party will be
required to indemnify any Indemnified Party with respect to any settlement
entered into without such Indemnifying Party's prior consent (which will not be
unreasonably withheld).

         8. ADJUSTMENT UPON CHANGES IN CAPITALIZATION. In the event of any
change in the Company Shares by reason of stock dividends, stock splits, reverse
stock splits, mergers (other than the Merger), recapitalizations, combinations,
exchanges of shares and the like, the type and number of shares or securities
subject to the Option, the Exercise Price will be adjusted appropriately, and
proper provision will be made in the agreements governing such transaction so
that Parent will receive, upon exercise of the Option, the number and class of
shares or other securities or property that Parent would have received in
respect of the Company Shares if the Option had been exercised immediately prior
to such event or the record date therefor, as applicable.

         9. RESTRICTIVE LEGENDS. Each certificate representing Option Shares
issued to Parent hereunder will include a legend in substantially the following
form:

         THE SECURITIES REPRESENTED BY THIS CERTIFICATE HAVE NOT BEEN REGISTERED
         UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY BE REOFFERED OR
         SOLD ONLY IF SO REGISTERED OR IF AN EXEMPTION FROM SUCH REGISTRATION IS
         AVAILABLE. SUCH SECURITIES ARE ALSO SUBJECT TO ADDITIONAL RESTRICTIONS
         ON TRANSFER AS SET FORTH IN THE STOCK OPTION AGREEMENT DATED


                                      -7-

<PAGE>

         AS OF JUNE 20, 2000, A COPY OF WHICH MAY BE OBTAINED FROM THE ISSUER.

         It is understood and agreed that (i) the reference to restrictions
arising under the Securities Act in the above legend will be removed by delivery
of substitute certificate(s) without such reference if such Option Shares have
been registered pursuant to the Securities Act, such Option Shares have been
sold in reliance on and in accordance with Rule 144 under the Securities Act or
Holder has delivered to Registrant a copy of a letter from the staff of the SEC,
or an opinion of counsel in form and substance reasonably satisfactory to
Registrant and its counsel, to the effect that such legend is not required for
purposes of the Securities Act and (ii) the reference to restrictions pursuant
to this Agreement in the above legend will be removed by delivery of substitute
certificate(s) without such reference if the Option Shares evidenced by
certificate(s) containing such reference have been sold or transferred in
compliance with the provisions of this Agreement under circumstances that do not
require the retention of such reference.

         10. LISTING AND HSR FILING. The Company, upon the request of Parent,
will promptly file an application to list the Company Shares to be acquired upon
exercise of the Option for quotation on the Nasdaq National Market and will use
its best efforts to obtain approval of such listing as soon as practicable.
Promptly after the date hereof, each of the parties hereto will promptly file
with the Federal Trade Commission and the Antitrust Division of the United
States Department of Justice all required premerger notification and report
forms and other documents and exhibits required to be filed under the HSR Act to
permit the acquisition of the Company Shares subject to the Option at the
earliest possible date.

         11. BINDING EFFECT. This Agreement will be binding upon and inure to
the benefit of the parties hereto and their respective successors and permitted
assigns. Nothing contained in this Agreement, express or implied, is intended to
confer upon any person other than the parties hereto and their respective
successors and permitted assigns any rights or remedies of any nature whatsoever
by reason of this Agreement. Any shares sold by a party in compliance with the
provisions of Section 7 will, upon consummation of such sale, be free of the
restrictions imposed with respect to such shares by this Agreement and any
transferee of such shares will not be entitled to the rights of such party.
Certificates representing shares sold in a registered public offering pursuant
to Section 7 will not be required to bear the legend set forth in Section 9.

         12. SPECIFIC PERFORMANCE. The parties hereto recognize and agree that
if for any reason any of the provisions of this Agreement are not performed in
accordance with their specific terms or are otherwise breached, immediate and
irreparable harm or injury would be caused for which money damages would not be
an adequate remedy. Accordingly, each party hereto agrees that in addition to
other remedies the other party hereto will be entitled to an injunction
restraining any violation or threatened violation of the provisions of this
Agreement or the right to enforce any of the covenants or agreements set forth
herein by specific performance. In the event that any action will be brought in
equity to enforce the provisions of the Agreement, neither party hereto will
allege, and each party hereto hereby waives the defense, that there is an
adequate remedy at law.

         13. ENTIRE AGREEMENT. This Agreement and the Reorganization Agreement
(including the appendices thereto) constitute the entire agreement between the
parties hereto with respect to the


                                      -8-

<PAGE>

subject matter hereof and supersede all other prior agreements and
understandings, both written and oral, between the parties hereto with respect
to the subject matter hereof.

         14. FURTHER ASSURANCES. Each party hereto will execute and deliver all
such further documents and instruments and take all such further action as may
be necessary in order to consummate the transactions contemplated hereby.

         15. VALIDITY. The invalidity or unenforceability of any provision of
this Agreement will not affect the validity or enforceability of the other
provisions of this Agreement, which will remain in full force and effect. In the
event any Governmental Entity of competent jurisdiction holds any provision of
this Agreement to be null, void or unenforceable, the parties hereto will
negotiate in good faith and will execute and deliver an amendment to this
Agreement in order, as nearly as possible, to effectuate, to the extent
permitted by law, the intent of the parties hereto with respect to such
provision.

         16. NOTICES. All notices and other communications hereunder will be in
writing and will be deemed given if delivered personally or by commercial
delivery service, or sent via telecopy (receipt confirmed) to the parties at the
following addresses or telecopy numbers (or at such other address or telecopy
numbers for a party as will be specified by like notice):

                  (a)      if to Parent, to:

                           Commerce One, Inc.
                           4440 Rosewood Drive
                           Pleasanton, California  94588
                           Attention: Robert Tarkoff
                           Telephone No.: 925-520-6000
                           Telecopy No.:  925-520-6066

                           with a copy to:

                           Wilson, Sonsini, Goodrich & Rosati, P.C.
                           650 Page Mill Road
                           Palo Alto, California 94304-1050
                           Attention:  Larry W. Sonsini, Esq.
                                       N. Anthony Jeffries, Esq.
                           Telephone No.: (650) 493-9300
                           Telecopy No.: (650) 493-6811


                                      -9-

<PAGE>

                  (b)      if to the Company, to:

                           Appnet, Inc.
                           6707 Democracy Boulevard
                           Suite 1000
                           Bethesda, Maryland 20817
                           Attention:  Ken Bajaj
                           Telephone No.: 301-493-8900
                           Telecopy No.: 301-581-2488

                           with a copy to:

                           Mayer, Brown & Platt
                           1675 Broadway
                           New York, NY  10019
                           Attention: James B. Carlson
                           Telephone No.: 212-506-2515
                           Telecopy No.:  212-849-5515

         17. GOVERNING LAW. This Agreement will be governed by and
construed in accordance with the laws of the State of Delaware applicable to
agreements made and to be performed entirely within such State.

         18. EXPENSES. Except as otherwise expressly provided herein or in
the Reorganization Agreement, all costs and expenses incurred in connection with
the transactions contemplated by this Agreement will be paid by the party
incurring such expenses.

         19. AMENDMENTS; WAIVER. This Agreement may be amended by the
parties hereto and the terms and conditions hereof may be waived only by an
instrument in writing signed on behalf of each of the parties hereto, or, in the
case of a waiver, by an instrument signed on behalf of the party waiving
compliance.

         20. ASSIGNMENT. Neither of the parties hereto may sell, transfer,
assign or otherwise dispose of any of its rights or obligations under this
Agreement or the Option created hereunder to any other person, without the
express written consent of the other party, except that the rights and
obligations hereunder will inure to the benefit of and be binding upon any
successor of a party hereto.

         21. COUNTERPARTS. This Agreement may be executed in counterparts,
each of which will be deemed to be an original, but both of which, taken
together, will constitute one and the same instrument.


                                      -10-
<PAGE>

         IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be
executed by their respective duly authorized officers as of the date first above
written.

                                  COMMERCE ONE, INC.

                                  By:
                                     ------------------------------------------

                                  Name:
                                       ----------------------------------------

                                  Title:
                                        ---------------------------------------


                                  APPNET, INC.

                                  By:
                                     ------------------------------------------

                                  Name:
                                       ----------------------------------------

                                  Title:
                                        ---------------------------------------





                   [SIGNATURE PAGE TO STOCK OPTION AGREEMENT]