Error message
A quick note. I just spent 10 frustrating minutes trying to figure out the following error message:
C:\ ... java:20: type parameters of <U>U cannot be determined; no unique maximal instance exists for type variable U with upper bounds java.lang.String,java.util.Collection<java.lang.String>
public String getPatternNames() { return CollectionManager.copyInto(patternNames, ArrayList.class); }
^
1 error
Tool completed with exit code 1
The source code was the following:
private List<String> patternNames;
public String getPatternNames(){return CollectionManager.copyInto(patternNames, ArrayList.class);}
This error message was so confusing that I didn't notice the immediately obvious:
publicString getPatternNames()
should have been
publicList<String> getPatternNames()
Changing the return type to the above fixed the error immediately.
However, it seems that javac throws this weird compilation error rather than the more sensible
C:\ ... java:20: incompatible types
found: java.util.List<java.lang.String>
required: java.lang.String
1 error
that it perhaps should have, simply because it was dealing with a generic method (CollectionManager.copyInto( ) which is generic).
Just a heads up (is this a bug btw?)
