Java 9 compiler fails with the following error (for similar code):
Error:(4, 9) java: UTF8 representation for string "LMain$Clazz<LMain$Cl..." is too long for the constant pool
Error:(4, 9) java: UTF8 representation for string "LMain$Clazz<LMain$Cl..." is too long for the constant pool
Four 'Inner's work. Five gives error:
The type generates a string that requires more than 65535 bytes to encode in Utf8 format in the constant pool
This is using Eclipse. So it is the Eclipse compiler which is integrated with the editor. I haven't tried Oracle's Java compiler.
Because the problem is to do with the size of a class constant pool, the limit of four Inner's should be universal across Java compilers, IDEs, and Operating Systems. (Assuming the class name mangling algorithm is part of the class specification.)
Here the generic signature which is a String is just too big, the dictionary part of the classfile, the constant pool, stores a String as an UTF8 byte array prefixed by its size on 16bits (hence the 65535 limit).