# Java: Summary: Arrays 2

Take a look at Summary: Arrays 1, which summarizes the basic array ideas before reading this.

Predefined array methods
[TODO] | See Array Library Methods until this summary is written.
Two-dimensional arrays
[TODO] | See Arrays - 2-dimensional until this summary is written.
Related ideas
ArrayList. | A common alternative is `java.util.ArrayList` which expands as necessary, but can only store object references, not primitive values.
Strings | are similar to arrays, but are specialized for characters by having a number of instance functions for working with character data.
C++ | arrays look similar, but differ in important features. The size may be specified in the declaration, no subscript range check is performed, and the length can not generally be accessed.