JDK15

• Hidden Classes
• Text Blocks
• ZGC支持增加
• sealed类(preview), 限制子类继承
  • public sealed class Animal permits Cat, Dog {}
  • public final class Cat extends Animal {}
  • public sealed class Dog extends Animal permits Husky {}
  • public final class Husky extends Dog {}
• CharSequence interface添加default isEmpty()
• TreeMap添加方法
  • putIfAbsent()
  • computeIfAbsent()
  • computeIfPresent()
  • compute()
  • merge()
• 正式版: 文本块