詳解JVM棧溢出和堆溢出

更新時(shí)間：2021年06月09日 15:39:34 作者：學(xué)而不思則忘

今天帶大家學(xué)習(xí)的是Java的相關(guān)知識(shí),文章圍繞著JVM棧溢出和堆溢出展開,文中有非常詳細(xì)的介紹及代碼示例,需要的朋友可以參考下

一、棧溢出StackOverflowError

棧是線程私有的，生命周期與線程相同，每個(gè)方法在執(zhí)行的時(shí)候都會(huì)創(chuàng)建一個(gè)棧幀，用來存儲(chǔ)局部變量表，操作數(shù)棧，動(dòng)態(tài)鏈接，方法出口等信息。

棧溢出：方法執(zhí)行時(shí)創(chuàng)建的棧幀個(gè)數(shù)超過了棧的深度。

原因舉例：方法遞歸

【示例】：

public class StackError {
    private int i = 0;

    public void fn() {
        System.out.println(i++);
        fn();
    }

    public static void main(String[] args) {
        StackError stackError = new StackError();
        stackError.fn();
    }
}

【輸出】：

解決方法：調(diào)整JVM棧的大?。?code>-Xss

-Xss size

Sets the thread stack size (in bytes). Append the letter k or K to indicate KB, m or M to indicate MB, and g or G to indicate GB. The default value depends on the platform:
Linux/x64 (64-bit): 1024 KBmacOS (64-bit): 1024 KBOracle Solaris/x64 (64-bit): 1024 KBWindows: The default value depends on virtual memory
The following examples set the thread stack size to 1024 KB in different units:

-Xss1m
-Xss1024k
-Xss1048576

This option is similar to -XX:ThreadStackSize.

在IDEA中點(diǎn)擊Run菜單的Edit Configuration如下圖：

設(shè)置后，再次運(yùn)行，會(huì)發(fā)現(xiàn)i的值變小，這是因?yàn)樵O(shè)置的-Xss值比原來的小：

二、堆溢出OutOfMemoryError:Java heap space

堆中主要存放的是對(duì)象。

堆溢出：不斷的new對(duì)象會(huì)導(dǎo)致堆中空間溢出。如果虛擬機(jī)的棧內(nèi)存允許動(dòng)態(tài)擴(kuò)展，當(dāng)擴(kuò)展棧容量無法申請(qǐng)到足夠的內(nèi)存時(shí)。

【示例】：

public class HeapError {
    public static void main(String[] args) {
        List<String> list = new ArrayList<>();

        try {
            while (true) {
                list.add("Floweryu");
            }
        } catch (Throwable e) {
            System.out.println(list.size());
            e.printStackTrace();
        }
    }
}

【輸出】：

解決方法：調(diào)整堆的大?。?code>Xmx

-Xmx size

Specifies the maximum size (in bytes) of the memory allocation pool in bytes. This value must be a multiple of 1024 and greater than 2 MB. Append the letter k or K to indicate kilobytes, m or M to indicate megabytes, and g or G to indicate gigabytes. The default value is chosen at runtime based on system configuration. For server deployments, -Xms and -Xmx are often set to the same value. The following examples show how to set the maximum allowed size of allocated memory to 80 MB by using various units:

-Xmx83886080
-Xmx81920k
-Xmx80m

The -Xmx option is equivalent to -XX:MaxHeapSize.