My coworker suggested making several of the Eclipse code-formatting and warning settings to be more rigorous. The majority of these changes make sense, but I get this one weird warning in Java. Here&#39;s some test code to reproduce the &quot;problem&quot;:

    package com.example.bugs;
    
    public class WeirdInnerClassJavaWarning {
    	private static class InnerClass
    	{
    		public void doSomething() {}
    	}
    		
    	final private InnerClass anInstance;
    	
    	{
    		this.anInstance = new InnerClass();   // !!!
    		this.anInstance.doSomething();
    	}
    }
    // using &quot;this.anInstance&quot; instead of &quot;anInstance&quot; prevents another warning,
    // Unqualified access to the field WeirdInnerClassJavaWarning.anInstance 	

The line with the !!! gives me this warning in Eclipse with my new warning settings:

&gt; Access to enclosing constructor
&gt; WeirdInnerClassJavaWarning.InnerClass()
&gt; is emulated by a synthetic accessor
&gt; method. Increasing its visibility will
&gt; improve your performance.

What does this mean? The warning goes away when I change &quot;private static class&quot; to &quot;protected static class&quot;, which makes no sense to me.


----------


**edit:** I finally figured out the &quot;correct&quot; fix. The real problem here seems to be that this nested private static class is missing a public constructor. That one tweak removed the warning:

    package com.example.bugs;
    
    public class WeirdInnerClassJavaWarning {
    	private static class InnerClass
    	{
    		public void doSomething() {}
    		public InnerClass() {}
    	}
    		
    	final private InnerClass anInstance;
    	
    	{
    		this.anInstance = new InnerClass();
    		this.anInstance.doSomething();
    	}
    }

I want the class to be a private nested class (so no other class can have access to it, including subclasses of the enclosing class) and I want it to be a static class.

I still don&#39;t understand why making the nested class protected rather than private is another method of fixing the &quot;problem&quot;, but maybe that is a quirk/bug of Eclipse.

(apologies, I should have called it NestedClass instead of InnerClass to be more clear.)

All Java Synthetic-Methods Solutions on Gang of Coders

Total of 1 Java Synthetic-Methods Solutions

Eclipse warning about synthetic accessor for private static nested classes in Java?