3.10.7 The Null Literal
The null type has one value, the null reference, represented by the literal null, which is formed from ASCII characters. A null literal is always of the null type.
4.12.5 Initial Values of Variables
For all reference types (§4.3), the default value is null.
William Brogden wrote:Given that all Java memory allocation sets the locations to zero, the value in memory for a null reference is zero.
If you set a variable to null, then what the actual bits of the reference in memory look like depends on JVM implementation details. It doesn't necessarily have to be zeroes. But it's not something you need to be concerned about, because you can't access the direct value of a reference variable anyway.