Garbage Collection

• Before Java 9, the default memory Garbage Collector for the JVM was called Parallel.

• With the arrival of Java 9, a new collection algorithm known as G1 became the default.

• G1 uses a different version of the algorithm with each successive Java version, with important differences in terms of performance and other behaviours.

• Hence, it is important that, when upgrading from Java 8 to a later version, a full performance retest is necessary.

• It allows the user to specify pause goals in terms of how long and how often the Stop The World pause occurs during garbage collection.