CompletableFuture<Integer> () { DebuggerManagerThreadImpl.assertIsManagerThread(); checkValid(); if (myFrameIndex == -1) { return myThreadProxy.frameCountAsync().thenApply(count -> { if (myFrameFromBottomIndex > count) { throw new CompletionException(EvaluateExceptionUtil.createEvaluateException(new IncompatibleThreadStateException())); } myFrameIndex = count - myFrameFromBottomIndex; return myFrameIndex; }); } return CompletableFuture.completedFuture(myFrameIndex); }