V6115. Not all Closeable members are released inside the 'close' method.

The analyzer has detected fields (resources) in the class implementing the 'Closeable' (or 'AutoCloseable') interface. The fields also implement this interface but are not released in the 'close' method of the class.

class A implements Closeable {

  private FileWriter resource;
 
  public A(String name) {
    resource = new FileWriter(name); 
  }

  public void close() {
    // resource is not released
  }
}

In this example, a developer initializes the 'resource' field but does not call the 'close' method within the 'A' class. The absence of the 'close' method results in the resource not being released even when the 'close' method is called for an object of the 'A' class. A program logic error may occur. For example, if a resource is not released, it cannot be accessed from another part of the code.

Such an error may persist even if the resource is closed in one of the methods:

class A implements Closeable {

  private FileWriter resource;

  public A(String name) {
    resource = new FileWriter(name); 
  }

  public void endWrite() {
    resource.close();
  }

  public void close() {
    // resource is not released, the endWrite method is not called 
  }
}

We can fix it in several ways. One of them is to release the resource inside the 'close' method of the class:

class A implements Closeable {

  private FileWriter resource;

  public A(String name) {
    resource = new FileWriter(name); 
  }

  public void close() {
    resource.close();
  }
}

Another option to fix it is to add the method call that closes the resource in the 'close' method:

class A implements Closeable {

  private FileWriter resource;

  public A(String name) {
    resource = new FileWriter(name); 
  }

  public void endWrite() {
    resource.close();
  }

  public void close() {
    endWrite(); 
  }
}

This diagnostic is classified as:

CWE-404