how to get reference method for class in intellj plugin

You can't (directly). However, you can filter them out programmatically like this: `ReferenceSearch.search(element).forEach(ref -> { if (!isInside(ref, classB)) handle(ref); })`. 

where 

```

boolean isInside(PsiReference ref, PsiElement aClass) {

return PsiTreeUtil.isAncestor(aClass, ref.getElement(), false);

}

```

it does not work in this case 

public class A { public void sum() {}}
public class B extends A{ }
public class D extends A{ }

it returns the usage of  the sum method in D class
I need the method usages for a specific class 

If you need usages from your specific class only, please try

<code>ReferenceSearch.search(element).forEach(ref -> { if (isInside(ref, yourSpecificClass)) handle(ref); return true; })</code>

it didn't return a result, the result should be the method usages for class B only 
can you check

No, ReferenceSearch.search(element).forEach() doesn't return the result, it passes the found usages to the processor instead, where you can store the usages to the collection, for example.

E.g.

{code}

List<PsiReference> usagesInClassA = new ArrayList<>();

ReferenceSearch.search(element).forEach(ref -> { if (isInside(ref, classA)) usagesInClassA.add(ref); return true; })

{code}

it does not work 
please refer to 

public Collection<PsiReference> searchMethod(PsiMethod method, PsiClass aClass) {
    List<PsiReference> psiReferences = new ArrayList<>();
    ReferencesSearch.search(method, GlobalSearchScope.projectScope(project), true).forEach(new Consumer<PsiReference>() {
        @Override
        public void accept(PsiReference psiReference) {
            if (isInside(psiReference, aClass)) {
                psiReferences.add(psiReference);
            }
        }
    });

    return psiReferences;
}

Excellent, I'm glad you've figured it out.

I meant it doesn't work it return an empty result