In Enum valueOf, if enumType is null, it failed to compile.


import java.util.*;
import java.lang.reflect.*;

public class TestEnum {

   public static void main(String[] args) {
        try {
             Colour02 test = Enum.valueOf(null, "BLUE");
             System.out.println("Test Fail");
        } catch(NullPointerException e) {
           System.out.println("Test Pass");
       }
   }

}

enum Colour02 {
     RED,YELLOW,GREEN,BLUE,PINK,BLACK;

}


javac result:

javac TestEnum.java
TestEnum.java:8: error: incompatible types: invalid inferred types for T#1
             Colour02 test = Enum.valueOf(null, "BLUE");
                                         ^
    reason: inferred type does not conform to upper bound(s)
      inferred: T#2
      upper bound(s): Colour02,Enum<T#2>
  where T#1,T#2 are type-variables:
    T#1 extends Enum<T#1> declared in method <T#1>valueOf(Class<T#1>,String)
    T#2 extends Colour02
1 error