java中类变量和方法局部变量的初始化

public class TestClass {String iStr;int i;public static void main(String[] args) {        TestClass tc = new TestClass();        String lStr; // local variable        int i; // local variable        System.out.println("tc.iStr = " + tc.iStr);        System.out.println("tc.i = " + tc.i);    //    System.out.println("lStr = " + lStr);//报错    //    System.out.println("i = " + i);//报错      }}