Description geoff bland 2021-06-17 08:50:05 EDT

This worked fine in Eclipse 2019.06 but has been broken in each version since. This affects us as we have many "cached" resources that are giving false positives potentially masking real issues if we need to mark all the false positives to ignore.

Example code. We have a wrapper class that encapsulates a resource, here we just keep it for the life of application and provide a reference to any other class that needs it. Note we provide the reference in two ways. 

package test_utilities;

import javax.sql.DataSource;

public class ExampleResourceWrapper {

	private static ExampleResource internalDataSourceSingleton;

	public ExampleResourceWrapper() {
		initialise();
	}

	private static void initialise() {
		if (internalDataSourceSingleton == null) {
			// Keeps the database open until we shutdown
		  internalDataSourceSingleton = new ExampleResource();
		}
	}
	
	public static DataSource getDataSource1() {
		return internalDataSourceSingleton;
	}
	
	public static ExampleResource getDataSource2() {
		return internalDataSourceSingleton;
	}
}

The ExampleResource class just subclasses the AutoCloseable class to show the issue.

package test_utilities;

import org.apache.commons.dbcp2.BasicDataSource;

public class ExampleResource extends BasicDataSource {
	// Just a wrapper
}

Here's some code using the cached resource and showing the issue:

package test_utilities;

import javax.sql.DataSource;

public class ExampleResourceLeak {

	public static void main(String[] args) {

		// As expected no warning here 
		DataSource ds1 = ExampleResourceWrapper.getDataSource1();
		
		// False positive "potential resource leak" warning here
		DataSource ds2 = ExampleResourceWrapper.getDataSource2();

		// Code just to remove the not used warning
		ds1.getClass();
		ds2.getClass();
	}

}


So why does ExampleResourceWrapper.getDataSource1() work as expected and not show an error but ExampleResourceWrapper.getDataSource2() shows the False positive "potential resource leak" warning.