If you are working with classes which have static initializers such as:

package com.example;

public class ClassWithStaticInitializer {
        private static Handler mHandler = new Handler();

As mHandler belongs to ClassWithStaticInitializer.class not instance of ClassWithStaticInitializer, JVM will initialize this mHandler as soon as execution starts, thus we will not get a chance to mock it with whenNew(). In this case, we can suppress its initialization and later set its value with Whitebox.

Here is an example to suppress mHandler in ClassWithStaticInitializer.class:

public class ClassWithStaticInitializerTest {
        // now when we call
        public void setup throws Exception {
                // At this stage, ClassWithStaticInitializer.mHandler will be null
                Whitebox.setInternalState(ClassWithStaticInitializer.class, "mHandler", mckHandler);

tip: if you see any error with StackTrace containing similar looking line com.examlpe.ExampleClass.<clinit>. It means there is an static initializer, just add com.examlpe.ExampleClass in your SuppressStaticInitializationFor annotation.

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