Dummy values of serialized variable

Question

Why default values as Zero are displayed for transient variables in Java?

How does it know that the value should be 0 for integer and null for String?

Answer 1

It knows that because that's how it's specified. Default value for int is 0, and default value for String is null.

Answer 2

From DOCS

It's not always necessary to assign a value when a field is declared. Fields that are declared but not initialized will be set to a reasonable default by the compiler. Generally speaking, this default will be zero or null, depending on the data type.

Answer 3

Default value of an int is 0 and a String is null

Answer 4

The default values for fields is defined by the JLS. Making it transient gives a hint that it won't be set and thus have the default value.

Answer 5

How does it know that the value should be 0 for integer and null for String?

Because that's the default, defined in the Java Language Specification.