package top.qaqaq.java.P479;

import org.junit.jupiter.api.Test;

/**
 * @author RichieZhang
 * @create 2022-10-23 下午 4:34
 */
public class IDEADebug {

    @Test
    public void testStringBuffer() {
        String str = null;
        StringBuffer sb = new StringBuffer();
        sb.append(str);//

        System.out.println(sb.length());//4

        System.out.println(sb);//"null"

        StringBuffer sb1 = new StringBuffer(str);//抛异常NullPointerException
        System.out.println(sb1);//
    }
}