Apply formatting rules and organize imports.
Replace appending single char String literals by a character literal.

Appending strings with single characters to buffers or streams is slower
than appending just the single character.
Boolean literals should never be used in equality tests.

Comparing the result of an expression to the literal value "false"
is not necessary and usually makes the code harder to read. Consider
negating the expression and removing the equality test.

Comparing the result of an expression to the literal value "true"
is not necessary and usually makes the code harder to read. Consider
removing the equality test.
Extra semicolons clutter the code and serve no useful purpose.
Use charAt() rather than startsWith() when the constant is a single character string.

Use charAt(0) rather than startsWith("string constant") when the constant
is a single character string. Using startsWith() with a one character argument
works, but it makes several computations while preparing to compare its prefix
with another string, which is unnecessary when you just want to compare one
character against another.
Methods that override other methods should do more than invoke the overridden method.