public class Test implements AutoCloseable {
	private Resource res = new Resource();
	
	private static class Resource implements AutoCloseable {
		private boolean closed = false;
		@Override
		public void close() throws Exception {
			assert !closed: "double close!";
			closed = true;
		}
		
		public void bar() {
			
		}
	}
	
	private Object getResource() {
		return res;
	}
	
	private void foo() {
		Object obj = getResource();
		
		if (obj instanceof Resource) {
			Resource r = (Resource)obj; // warning Resource leak: 'r' is never closed
			r.bar();			
		}
	}
	
	private void fooFixed() throws Exception {
		Object obj = getResource();
		
		if (obj instanceof Resource) {
			try(Resource r = (Resource)obj) {
				r.bar();			
			}
		}		
	}
	
	@Override
	public void close() throws Exception {
		res.close();
	}
	
	public static void main(String[] args) {
		try(Test test = new Test()) {
			test.fooFixed();
		}
		catch (Exception e) {
			
		}
	}
}