InnerClassLeakActivity.java

package pl.pszklarska.leakexample;

public class InnerClassLeakActivity extends AppCompatActivity {

    @Override
    protected void onCreate(@Nullable final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        
        InnerClass innerClassInstance = new InnerClass();
        innerClassInstance.showToast();
    }

    private class InnerClass {
        void showToast() {
            new Handler().postDelayed(() -> makeSomeAction(), TimeUnit.MINUTES.toMillis(10));
        }
    }
}