阅读下面程序 public class ConcatTest { public static void main(String[] args) { String str1="abc"； String str2="ABC"： String str3=str1.concat(str2)； System.out.println(str3)； } } 程序运行的结果是

A．abc

B．ABC

C．abcABC

D．ABCabc

[单选题]阅读下面程序 public class ConcatTest{ public static void main(String[] args) { String strl = "abc"; String str2 = "ABC"; String str3 = str1.concat(str2); System.out.println(str3); } } 程序的运行结果是：A．abeB．ABCC．abcABCD．ABCabc

[单选题]阅读下面程序 public class ConcatTest{ public static void main(String[] args) { String strl = "abc"; String str2 = "ABC"; String str3 = str1.concat(str2); System.out.println(str3); } } 程序的运行结果是：A．abeB．ABCC．abcABCD．ABCabc

[单选题]阅读下面程序public class ConcatTest{P ublic static void main(String[] args){S tring str1 = " abc " ;S tring str2 = " ABC " ;S tring str3 = str1.concat(str2);S ystem.out.println(str3);}}程序的运行结果是A．)abcB．)ABCC．)abcABCD．)ABCabc

[单选题]请阅读下面程序 public class ThreadTest{ public static void main(String args[]) ( Thread t1=new Thread(new Hello()); Thread t2=new Thread(new Hello()); t1.start(); t2.start(); } } class Hello implements Runnable { int i; public void run() { while(true) { Sys

[单选题]请阅读下面程序 public class ThreadTest{ public static void main(String args[]) ( Thread t1=new Thread(new Hello()); Thread t2=new Thread(new Hello()); t1.start(); t2.start(); } } class Hello implements Runnable { int i; public void run() { while(true) { Sys

[单选题]阅读下面程序 public class Test2______ { public static void main(String[] args){ Thread t=new Test2(); t. start(); } public void run(){ System. out. priatln("How are you. "); } } 在程序下画线处填入的正确的选项是A．implements ThreadB．extends RunnableC．implements RunnableD．

[单选题]阅读下面程序 public class Test2______ { public static void main(String[] args){ Thread t=new Test2(); t. start(); } public void run(){ System. out. priatln("How are you. "); } } 在程序下画线处填入的正确的选项是A．implements ThreadB．extends RunnableC．implements RunnableD．

[单选题]阅读下面程序 public class VariableUse { public static void main(String[] arqs) { int a； if(a==8) { int b=9； System.out.println("a="+a)； System.out.println("b="+b)； } System.out.println("a="+a)； System.out.println("b="+b)： } } 该程序在编译时的结果是A．变量a未赋值B．第

[单选题]阅读下面程序： public class ThreadTest { public static void main(String args[]) throws Exception { int i=0; Hello t=new Hello()； ______； While(true) } System.out.println("Good Morning"+i++)； if(i==2&&t.isAlive()) { System.out.println("Main waitin

[单选题]阅读下面程序 public class Increment { public static void main( String args[] ){ int c; c=5; System.out.println(C) ; System.out.println(c++); System.out.println(C) ; } }A．5 6 6B．5 5 6C．6 7 7D．6 6 6