To address the question more generally...
Keep in mind that using synchronized on methods is really just shorthand (assume class is SomeClass):
synchronized static void foo() {
...
}
is the same as
static void foo() {
synchronized(SomeClass.class) {
...
}
}
and
synchronized void foo() {
...
}
is the same as
void foo() {
synchronized(this) {
...
}
}
You can use any object as the lock. If you want to lock subsets of static methods, you can
class SomeClass {
private static final Object LOCK_1 = new Object() {};
private static final Object LOCK_2 = new Object() {};
static void foo() {
synchronized(LOCK_1) {...}
}
static void fee() {
synchronized(LOCK_1) {...}
}
static void fie() {
synchronized(LOCK_2) {...}
}
static void fo() {
synchronized(LOCK_2) {...}
}
}
(for non-static methods, you would want to make the locks be non-static fields)