java.lang.NullPointerException
        at com.sun.tools.javac.code.Types$DefaultTypeVisitor.visit(Types.java:3183)
        at com.sun.tools.javac.code.Types.hasSameArgs(Types.java:1894)
        at com.sun.tools.javac.code.Types.isSubSignature(Types.java:1863)
        at com.sun.tools.javac.code.Symbol$MethodSymbol.overrides(Symbol.java:1123)
        at com.sun.tools.javac.model.JavacElements.overrides(JavacElements.java:536)
        at com.sun.tools.javac.model.JavacElements.addMembers(JavacElements.java:425)
        at com.sun.tools.javac.model.JavacElements.getAllMembers(JavacElements.java:413)
        at com.sun.tools.javac.model.JavacElements.getAllMembers(JavacElements.java:62)