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Java String codePoints() method String codePoints() method added jdk 9. This method Returns a stream of code point values from this sequence. Any surrogate pairs encountered in the sequence are combined as if by Character.toCodePoint and the result is passed to the stream. Any other code units, including ordinary BMP characters, unpaired surrogates, and undefined code units, are zero-extended to int values which are then passed to the stream. Java Program Example: class StringCodePoints{ public static void main(String args[]){ String str = "This is a String"; IntStream ins = str.codePoints().....// process with inStream api } }

Java String chars() method String chars() method added jdk 9. This method returns a stream of int zero-extending the char values from this sequence. Any char which maps to a surrogate code point is passed through uninterpreted. Java Program Example: class StringChars{ public static void main(String args[]){ String str = "This is a String"; IntStream ins = str.chars().....// process with inStream api } }

An Executor that provides methods to manage termination and methods that can produce a Future for tracking progress of one or more asynchronous tasks. An ExecutorService can be shut down, which will cause it to reject new tasks. Two different methods are provided for shutting down an ExecutorService. The shutdown() method will allow previously submitted tasks to execute before terminating, while the shutdownNow() method prevents waiting tasks from starting and attempts to stop currently executing tasks. Upon termination, an executor has no tasks actively executing, no tasks awaiting execution, and no new tasks can be submitted. An unused ExecutorService should be shut down to allow reclamation of its resources. Method submit extends base method Executor.execute(java.lang.Runnable) by creating and returning a Future that can be used to cancel execution and/or wait for completion. Methods invokeAny and invokeAll perform the most commonly useful forms of bulk execution, executing a c...

For formal parameters of implicitly typed lambda expressions, allow the reserved type name `var` to be used, so that:     (var x, var y) -> x.process(y) is equivalent to:     (x, y) -> x.process(y) An implicitly typed lambda expression must use `var` for all its formal parameters or for none of them. In addition, `var` is permitted only for the formal parameters of implicitly typed lambda expressions --- explicitly typed lambda expressions continue to specify manifest types for _all_ their formal parameters, so it is not permitted for some formal parameters to have manifest types while others use `var`. The following examples are illegal:     (var x, y) -> x.process(y)         // Cannot mix 'var' and 'no var' in implicitly typed lambda expression     (var x, int y) -> x.process(y)     // Cannot mix 'var' and manifest types in explicitly typed lambda expression In theory, it would be...

Recent experience performance problems caused by high concurrency, final positioning of the problem is that LinkedBlockingQueuethe performance is not, ultimately to reduce the competitive pressure of each Queue by creating multiple Queue. For the first time in my life, I encountered a situation where the JDK's own data structure could not meet the needs, and I was determined to study why. The pressure test is on a 40-core machine. Tomcat defaults to 200 threads. The sender sends 500 requests at about 1w QPS and requires a response of 999 quantiles at about 50ms. There is a task that writes to the database asynchronously in the code. In actual testing, more than 60% of the delay is in the write queue (in fact, the task is submitted to the ThreadPool). He began research LinkedBlockingQueueimplementation. Equivalent plus LinkedList LinkedBlockingQueue ordinary ReentrantLocklocking during operation. ReentrantLock (and other locks in Java) internally rely on CAS to achieve atomicit...