Java Programming/Keywords/boolean
boolean
is a keyword which designates the boolean
primitive type. There are only two possible boolean
values: true
and false
. The default value for boolean
fields is false
.
The following is a declaration of a private
boolean
field named initialized
, and its use in a method named synchronizeConnection
.
Code section 1: Connection synchronization.
private boolean initialized = false;
public void synchronizeConnection() {
if (!initialized) {
connection = connect();
initialized = true;
}
}
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The previous code only creates a connection once (at the first method call). Note that there is no automatic conversion between integer types (such as int
) to boolean
as is possible in some languages like C. Instead, one must use an equivalent expression such as (i != 0)
which evaluates to true
if i
is not zero.