JVM如何处理StackOverflowError

我们知道，当虚拟机栈容量太小或者栈帧太大时，程序都会抛出StackOverflowError异常，对于StackOverflowError的处理方法，有下面两种：

1. 通过try…catch(Throwable t){}来捕获，然后跟普通异常一样，对StackOverflowError进行处理
2. 不捕获，然后交给JVM处理，JVM此时会中断当前线程，但是不会影响其他线程，因为虚拟机栈是每个线程私有的

下面，我们分别来模拟一下两种方法：

1.捕获StackOverflowError

public class SOFTest { 
    public static void main(String[] args) { new Thread(new SOFClass(),"Sub thread").start(); while (true){ System.out.println("I am main thread!"); try { Thread.sleep(1000L); } catch (InterruptedException e) { e.printStackTrace(); } } } private static class SOFClass implements Runnable{ 
    @Override public void run() { try { recursiveMethod(); }catch (Throwable throwable){ System.out.println("捕获到了异常："+ throwable.getClass()); } while (true){ System.out.println("I am sub thread!"); try { Thread.sleep(1000L); } catch (InterruptedException e) { e.printStackTrace(); } } } public void recursiveMethod(){ recursiveMethod(); } } } //运行结果 I am main thread! 捕获到了异常：class java.lang.StackOverflowError I am sub thread! I am main thread! I am sub thread! I am main thread! I am sub thread! I am main thread! I am sub thread!

2.JVM处理StackOverflowError

下面，我们不捕获StackOverflowError异常，当我们没有捕获时，异常就交给了JVM去处理了。

public class SOFTest { public static void main(String[] args) { new Thread(new SOFClass(),"Sub thread").start(); while (true){ System.out.println("I am main thread!"); try { Thread.sleep(1000L); } catch (InterruptedException e) { e.printStackTrace(); } } } private static class SOFClass implements Runnable{ @Override public void run() { recursiveMethod(); } public void recursiveMethod(){ recursiveMethod(); } } } //运行结果 I am main thread! Exception in thread "Sub thread" java.lang.StackOverflowError at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) at com.arch.test.jvm.SOFTest$SOFClass.recursiveMethod(SOFTest.java:37) …… I am main thread! I am main thread! I am main thread! I am main thread! I am main thread! ……

我们可以看到，JVM中断了Sub thread，但是主线程仍然在运行，没有影响