In Java, trash, or garbage, is heap memory that a program allocates for objects but no longer references; such memory serves no useful purpose.

Copying objects is a common Java programming operation that has one serious trap. Here's how to avoid copying from an object reference and only copy the instance and values you want.

The reference variables within the method frames of each Java thread stack The first source is relatively easy to appreciate, but the second requires elaboration.

You can fix your Java memory leak problem without a costly JVM heap dump. Just use Java Flight Recorder's Old Object Sample event and view the recording in JDK Mission Control.