小编hbe*_*iro的帖子

阅读新Supplier界面我看不出它的用法有什么好处.我们可以看到它的一个例子.

class Vehicle{
  public void drive(){ 
    System.out.println("Driving vehicle ...");
  }
}
class Car extends Vehicle{
  @Override
  public void drive(){
    System.out.println("Driving car...");
  }
}
public class SupplierDemo {   
  static void driveVehicle(Supplier<? extends Vehicle> supplier){
    Vehicle vehicle = supplier.get();
    vehicle.drive();   
  }
}
public static void main(String[] args) {
  //Using Lambda expression
  driveVehicle(()-> new Vehicle());
  driveVehicle(()-> new Car());
}

正如我们在该示例中所看到的,该driveVehicle方法需要一个Supplieras参数.为什么我们不把它改成期待Vehicle？

public class SupplierDemo {   
  static void driveVehicle(Vehicle vehicle){
    vehicle.drive();   
  }
}
public static void main(String[] …

java选项-XX:-EliminateAllocations有什么作用？我找不到任何关于它的文档.

AttachNotSupportedException尝试开始JFR记录时收到提示。到现在为止，它一直在正常工作。

jcmd 3658 JFR.start maxsize=100M filename=jfr_1.jfr dumponexit=true settings=profile

输出：

3658:
com.sun.tools.attach.AttachNotSupportedException: Unable to open socket file: target process not responding or HotSpot VM not loaded
        at sun.tools.attach.LinuxVirtualMachine.<init>(LinuxVirtualMachine.java:106)
        at sun.tools.attach.LinuxAttachProvider.attachVirtualMachine(LinuxAttachProvider.java:63)
        at com.sun.tools.attach.VirtualMachine.attach(VirtualMachine.java:208)

可能会发生什么？

因此：Oracle Linux Server 6.7版

$ java -version
java version "1.8.0_102"
Java(TM) SE Runtime Environment (build 1.8.0_102-b14)
Java HotSpot(TM) 64-Bit Server VM (build 25.102-b14, mixed mode)