Can we assume default array values in Java? for example, assume that an int array is set to all zeros?

Question

In practice can I assume that all int arrays in Java will start out filled with zeros? for all machines in which the JVM runs?

Is this true for all types? char? bool

Answer 1

Java Language Specification is the right place to look for such information:

Array components are unnamed variables that are created and initialized to default values (§4.12.5) whenever a new object that is an array is created

Default values themselves are given in section 4.12.5.

• For type byte, the default value is zero, that is, the value of (byte)0.
• For type short, the default value is zero, that is, the value of (short)0.
• For type int, the default value is zero, that is, 0.
• For type long, the default value is zero, that is, 0L.
• For type float, the default value is positive zero, that is, 0.0f.
• For type double, the default value is positive zero, that is, 0.0d.
• For type char, the default value is the null character, that is, '\u0000'.
• For type boolean, the default value is false.
• For all reference types, the default value is null.