What are GC Roots?

GC Roots are special objects or references in memory from which the traversal of the object graph begins to determine reachability in the Java Garbage Collector.

Objects reachable from GC Roots are considered alive and are not subject to removal. If an object is not reachable from GC Roots, it is considered garbage and can be collected.

Examples of GC Roots:

• References from the current thread's stack (local variables and method parameters).
• References from static fields of classes.
• References from active JNI (Java Native Interface) objects.
• References from system classes and some internal JVM structures.

Thus, GC Roots are the roots from which the search for live objects in the heap begins, ensuring the correct operation of the garbage collector.