* 演示HashMap的线程不安全问题及解决方案 */publicclassThreadDemo4{publicstaticvoidmain(String[] args) {//Map<String,Object> map = new HashMap<>();//解决方法1:Collections//Map<String,Object> map = Collections.synchronizedMap(new HashMap<>());//解决方法2:ConcurrentHashMapMap<String,Object> ...