Why can't I "static import" an "equals" method in Java?

Question

I like using this method here:

org.apache.commons.lang.ObjectUtils.equals(Object object1, Object object2) 

The only drawback (compared to Google Guava, for instance), is that I cannot static import the method. I.e. this is useless:

import static org.apache.commons.lang.ObjectUtils.equals; 

... as my Eclipse compiler will not correctly link that method when writing

equals(obj1, obj2); 

The error is:

The method equals(Object) in the type Object is not applicable for the arguments (..., ...)

Why is that? Is my statically imported method not applicable if there is a method with the same name (but not the same signature) in any of the super types? Is this formally specified in the JLS? Or some Eclipse compiler issue?

UPDATE

This doesn't work either:

import static org.apache.commons.lang.ObjectUtils.defaultIfNull;  public class Test {   void test() {     defaultIfNull(null, null);     // ^^ compilation error here   }    void defaultIfNull() {   } } 

javac error message:

Test.java:5: defaultIfNull() in Test cannot be applied to (<nulltype>,<nulltype>) defaultIfNull(null, null);     ^ 1 error 

Answer 1

As per Java Language Specification

1. If a single-static-import declaration imports a member whose simple name is n, and the compilation unit also contains a single-type-import declaration that imports a type whose simple name is n, a compile-time error occurs. (This error occurs even if both declarations refer to the same type, on the grounds that it is confusing to use two different mechanisms to redundantly import the same type.)
2. If a single-static-import declaration imports a member whose simple name is n, and the compilation unit also declares a top level type whose simple name is n, a compile-time error occurs.

So in your case its point 2 mentioned above is the reason you are getting compile time error. so even if method signatures are different if there names are same its a compile time error.

static import JSR and JLS