[Java] Java并发的CAS原理与ABA问题的讲解

public final int addandget​(int delta)
atomically adds the given value to the current value, with memory effects as specified by varhandle.getandadd(java.lang.object…).
parameters:
delta - the value to add
returns:
the updated value

public final int addandget(int delta) {
  return u.getandaddint(this, value, delta) + delta;
}

private static final long value = u.objectfieldoffset(atomicinteger.class, "value");

/**
 * atomically adds the given value to the current value of a field
 * or array element within the given object {@code o}
 * at the given {@code offset}.
 * @param o object/array to update the field/element in
 * @param offset field/element offset
 * @param delta the value to add
 * @return the previous value
 * @since 1.8
 **/
@hotspotintrinsiccandidate
public final int getandaddint(object o, long offset, int delta) {
  int v;
  do {
  v = getintvolatile(o, offset);
  } while (!weakcompareandsetint(o, offset, v, v + delta));
  return v;
}

@hotspotintrinsiccandidate
public final boolean weakcompareandsetint(object o, long offset,
           int expected,
           int x) {
  return compareandsetint(o, offset, expected, x);
}