The Javadoc API documentation for java.util.Collections explains the basics of this class such as the fact that all of its methods are static and that they all either operate on a provided ...

java.lang.ref: A collection of reference-related language classes, such as SoftReference and ReferenceQueue, organized in the ref sub-subpackage of the java package’s lang subpackage ...

However, there are collection classes in Java that act like a Java array but resize themselves automatically. Any class that extends the List interface expands dynamically. Java arrays do not expand ...