Program: 64310
Project: 64310
Buggy source:
/** 
 * Executes the task.
 */
public void execute() throws BuildException {
  if ((sourceFileSets.size() == 0) && (sourceFileLists.size() == 0)) {
    throw new BuildException("String_Node_Str");
  }
  if ((targetFileSets.size() == 0) && (targetFileLists.size() == 0)) {
    throw new BuildException("String_Node_Str");
  }
  long now=(new Date()).getTime();
  if (Os.isFamily("String_Node_Str")) {
    now+=2000;
  }
  Vector allTargets=new Vector();
  long oldestTargetTime=0;
  File oldestTarget=null;
  Enumeration enumTargetSets=targetFileSets.elements();
  while (enumTargetSets.hasMoreElements()) {
    FileSet targetFS=(FileSet)enumTargetSets.nextElement();
    DirectoryScanner targetDS=targetFS.getDirectoryScanner(project);
    String[] targetFiles=targetDS.getIncludedFiles();
    for (int i=0; i < targetFiles.length; i++) {
      File dest=new File(targetFS.getDir(project),targetFiles[i]);
      allTargets.addElement(dest);
      if (dest.lastModified() > now) {
        log("String_Node_Str" + targetFiles[i] + "String_Node_Str",Project.MSG_WARN);
      }
      if (oldestTarget == null || dest.lastModified() < oldestTargetTime) {
        oldestTargetTime=dest.lastModified();
        oldestTarget=dest;
      }
    }
  }
  boolean upToDate=true;
  Enumeration enumTargetLists=targetFileLists.elements();
  while (enumTargetLists.hasMoreElements()) {
    FileList targetFL=(FileList)enumTargetLists.nextElement();
    String[] targetFiles=targetFL.getFiles(project);
    for (int i=0; i < targetFiles.length; i++) {
      File dest=new File(targetFL.getDir(project),targetFiles[i]);
      if (!dest.exists()) {
        log(targetFiles[i] + "String_Node_Str",Project.MSG_VERBOSE);
        upToDate=false;
        continue;
      }
 else {
        allTargets.addElement(dest);
      }
      if (dest.lastModified() > now) {
        log("String_Node_Str" + targetFiles[i] + "String_Node_Str",Project.MSG_WARN);
      }
      if (oldestTarget == null || dest.lastModified() < oldestTargetTime) {
        oldestTargetTime=dest.lastModified();
        oldestTarget=dest;
      }
    }
  }
  if (oldestTarget != null) {
    log(oldestTarget + "String_Node_Str",Project.MSG_VERBOSE);
  }
 else {
    upToDate=false;
  }
  if (upToDate) {
    Enumeration enumSourceLists=sourceFileLists.elements();
    while (upToDate && enumSourceLists.hasMoreElements()) {
      FileList sourceFL=(FileList)enumSourceLists.nextElement();
      String[] sourceFiles=sourceFL.getFiles(project);
      int i=0;
      do {
        File src=new File(sourceFL.getDir(project),sourceFiles[i]);
        if (src.lastModified() > now) {
          log("String_Node_Str" + sourceFiles[i] + "String_Node_Str",Project.MSG_WARN);
        }
        if (!src.exists()) {
          log(sourceFiles[i] + "String_Node_Str",Project.MSG_VERBOSE);
          upToDate=false;
          break;
        }
        if (src.lastModified() > oldestTargetTime) {
          upToDate=false;
          log(oldestTarget + "String_Node_Str" + sourceFiles[i],Project.MSG_VERBOSE);
        }
      }
 while (upToDate && (++i < sourceFiles.length));
    }
  }
  if (upToDate) {
    Enumeration enumSourceSets=sourceFileSets.elements();
    while (upToDate && enumSourceSets.hasMoreElements()) {
      FileSet sourceFS=(FileSet)enumSourceSets.nextElement();
      DirectoryScanner sourceDS=sourceFS.getDirectoryScanner(project);
      String[] sourceFiles=sourceDS.getIncludedFiles();
      for (int i=0; upToDate && i < sourceFiles.length; i++) {
        File src=new File(sourceFS.getDir(project),sourceFiles[i]);
        if (src.lastModified() > now) {
          log("String_Node_Str" + sourceFiles[i] + "String_Node_Str",Project.MSG_WARN);
        }
        if (src.lastModified() > oldestTargetTime) {
          upToDate=false;
          log(oldestTarget + "String_Node_Str" + sourceFiles[i],Project.MSG_VERBOSE);
        }
      }
    }
  }
  if (!upToDate) {
    log("String_Node_Str",Project.MSG_VERBOSE);
    for (Enumeration e=allTargets.elements(); e.hasMoreElements(); ) {
      File fileToRemove=(File)e.nextElement();
      log("String_Node_Str" + fileToRemove.getAbsolutePath(),Project.MSG_VERBOSE);
      fileToRemove.delete();
    }
  }
}

Fixed version (ground truth):
/** 
 * Executes the task.
 */
public void execute() throws BuildException {
  if ((sourceFileSets.size() == 0) && (sourceFileLists.size() == 0)) {
    throw new BuildException("String_Node_Str");
  }
  if ((targetFileSets.size() == 0) && (targetFileLists.size() == 0)) {
    throw new BuildException("String_Node_Str");
  }
  long now=(new Date()).getTime();
  if (Os.isFamily("String_Node_Str")) {
    now+=2000;
  }
  Vector allTargets=new Vector();
  long oldestTargetTime=0;
  File oldestTarget=null;
  Enumeration enumTargetSets=targetFileSets.elements();
  while (enumTargetSets.hasMoreElements()) {
    FileSet targetFS=(FileSet)enumTargetSets.nextElement();
    DirectoryScanner targetDS=targetFS.getDirectoryScanner(project);
    String[] targetFiles=targetDS.getIncludedFiles();
    for (int i=0; i < targetFiles.length; i++) {
      File dest=new File(targetFS.getDir(project),targetFiles[i]);
      allTargets.addElement(dest);
      if (dest.lastModified() > now) {
        log("String_Node_Str" + targetFiles[i] + "String_Node_Str",Project.MSG_WARN);
      }
      if (oldestTarget == null || dest.lastModified() < oldestTargetTime) {
        oldestTargetTime=dest.lastModified();
        oldestTarget=dest;
      }
    }
  }
  boolean upToDate=true;
  Enumeration enumTargetLists=targetFileLists.elements();
  while (enumTargetLists.hasMoreElements()) {
    FileList targetFL=(FileList)enumTargetLists.nextElement();
    String[] targetFiles=targetFL.getFiles(project);
    for (int i=0; i < targetFiles.length; i++) {
      File dest=new File(targetFL.getDir(project),targetFiles[i]);
      if (!dest.exists()) {
        log(targetFiles[i] + "String_Node_Str",Project.MSG_VERBOSE);
        upToDate=false;
        continue;
      }
 else {
        allTargets.addElement(dest);
      }
      if (dest.lastModified() > now) {
        log("String_Node_Str" + targetFiles[i] + "String_Node_Str",Project.MSG_WARN);
      }
      if (oldestTarget == null || dest.lastModified() < oldestTargetTime) {
        oldestTargetTime=dest.lastModified();
        oldestTarget=dest;
      }
    }
  }
  if (oldestTarget != null) {
    log(oldestTarget + "String_Node_Str",Project.MSG_VERBOSE);
  }
 else {
    upToDate=false;
  }
  if (upToDate) {
    Enumeration enumSourceLists=sourceFileLists.elements();
    while (upToDate && enumSourceLists.hasMoreElements()) {
      FileList sourceFL=(FileList)enumSourceLists.nextElement();
      String[] sourceFiles=sourceFL.getFiles(project);
      for (int i=0; upToDate && i < sourceFiles.length; i++) {
        File src=new File(sourceFL.getDir(project),sourceFiles[i]);
        if (src.lastModified() > now) {
          log("String_Node_Str" + sourceFiles[i] + "String_Node_Str",Project.MSG_WARN);
        }
        if (!src.exists()) {
          log(sourceFiles[i] + "String_Node_Str",Project.MSG_VERBOSE);
          upToDate=false;
          break;
        }
        if (src.lastModified() > oldestTargetTime) {
          upToDate=false;
          log(oldestTarget + "String_Node_Str" + sourceFiles[i],Project.MSG_VERBOSE);
        }
      }
    }
  }
  if (upToDate) {
    Enumeration enumSourceSets=sourceFileSets.elements();
    while (upToDate && enumSourceSets.hasMoreElements()) {
      FileSet sourceFS=(FileSet)enumSourceSets.nextElement();
      DirectoryScanner sourceDS=sourceFS.getDirectoryScanner(project);
      String[] sourceFiles=sourceDS.getIncludedFiles();
      for (int i=0; upToDate && i < sourceFiles.length; i++) {
        File src=new File(sourceFS.getDir(project),sourceFiles[i]);
        if (src.lastModified() > now) {
          log("String_Node_Str" + sourceFiles[i] + "String_Node_Str",Project.MSG_WARN);
        }
        if (src.lastModified() > oldestTargetTime) {
          upToDate=false;
          log(oldestTarget + "String_Node_Str" + sourceFiles[i],Project.MSG_VERBOSE);
        }
      }
    }
  }
  if (!upToDate) {
    log("String_Node_Str",Project.MSG_VERBOSE);
    for (Enumeration e=allTargets.elements(); e.hasMoreElements(); ) {
      File fileToRemove=(File)e.nextElement();
      log("String_Node_Str" + fileToRemove.getAbsolutePath(),Project.MSG_VERBOSE);
      fileToRemove.delete();
    }
  }
}