Question

I notice some people seem to differ when comparing two strings together, such as when comparing a variable to a constant. For example, let’s say we have a constant string and an input method:

public final String CONSTANT_STRING = "A constant string";
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

Is it better or faster in any way to use the unknown input first:

br.readLine().equals(CONSTANT_STRING)

or to compare the constant to the unknown:

CONSTANT_STRING.equals(br.readLine());

Answer 1

Its not a matter of performance. The second version won’t ever produce a NullPointerException, even when br.readLine() returns null. The first one does though.