Unicode 0x200B (zero-width whitespace) causes instrumentation failure

JDK 6 implements Unicode 4.0. In this version of Unicode, the zero-width whitespace character (0x200B) is being treated as a whitespace.

JDK 7 implements Unicode 6.0. In this version of Unicode, the zero-width whitespace has been reclassified to the 'format character' group (other characters in this group are, for example, left-/right- text direction markers).

Thus, Java compiler in JDK 6 allows to use 0x200B as a normal whitespace character, e.g. separating symbols.

The Java compiler since JDK 7 silently ignores the 0x200B, which means that it cannot be used to separate symbols anymore. However you can put this character virtually in any place, e.g.:

void this<200B>Is<200B>MyMethod();

Clover fails on parsing the 200B character:

Xyz.java:287:90:unexpected char: 0x200B
at com.atlassian.clover.instr.java.Instrumenter.instrument(Instrumenter.java:166)
at com.atlassian.clover.CloverInstr.execute(CloverInstr.java:76)
at com.atlassian.clover.CloverInstr.mainImpl(CloverInstr.java:54)
at ...

Planned fix:

• Ignore 200B characters in Java 7+. Treat 200B character as space in Java 6.
• Question: Shall it be based on source level setting or the JDK detected?
• Question: which other control characters needs to be ignored by Clover?
• Question: which other whitespace characters (other than space, \t, \n, \r) shall be recognized by Clover parser?

Workaround:

Remove all 200B character occurrences from the source code.