System.out.printf vs System.out.format
System.out is a PrintStream, and quoting the javadoc for PrintStream.printf
An invocation of this method of the form
out.printf(l, format, args)behaves in exactly the same way as the invocationout.format(l, format, args)
The actual implementation of both printf overloaded forms
public PrintStream printf(Locale l, String format, Object ... args) { return format(l, format, args);}and
public PrintStream printf(String format, Object ... args) { return format(format, args);}uses the format method's overloaded forms
public PrintStream format(Locale l, String format, Object ... args)and
public PrintStream format(String format, Object ... args)respectively.