Diamond operator type inference fails under javac but not ECJ

[datho7561]

The following minimal example produces a compiler error under javac but not ECJ:

import java.util.List;
import java.util.ArrayList;
import java.util.Arrays;

public class HelloWorld {
	public static void main(String... args) {
		Class[] classes = new Class[] { String.class, List.class };
		List<Class<?>> asdf = new ArrayList<>(Arrays.asList(classes));
	}
}

Here's the error that javac gives:

HelloWorld.java:9: error: incompatible types: cannot infer type arguments for ArrayList<>
                List<Class<?>> asdf = new ArrayList<>(Arrays.asList(classes));
                                                   ^
    reason: cannot infer type-variable(s) E,T
      (argument mismatch; List<Class> cannot be converted to Collection<? extends Class<?>>)
  where E,T are type-variables:
    E extends Object declared in class ArrayList
    T extends Object declared in method <T>asList(T...)

[stephan-herrmann]

$ ecj  -23 -warn:+all HelloWorld.java 
----------
1. WARNING in /tmp/HelloWorld.java (at line 7)
        Class[] classes = new Class[] { String.class, List.class };
        ^^^^^
Class is a raw type. References to generic type Class<T> should be parameterized
----------

Let's not spend time on compiler difference where raw types are involved. Those are legacy since about 20 years. Knowing that javac has some significant, long standing bugs in this area, we can simply blame them :)