publicclassIntegerCheck{publicstaticvoidmain(String[]args){Integervalue1=null;Integervalue2=10;System.out.println("Value1: "+checkInteger(value1));// 输出 "Value1: null"System.out.println("Value2: "+checkInteger(value2));// 输出 "Value2: 10"}publicstaticStringcheckInteger(Integervalue){if...
方法一:使用包装类Integer Java中的包装类Integer可以表示int值,并且可以为null。通过将int值赋值给Integer对象,我们可以方便地判断int值是否为空。 IntegerintValue=null;intnum=0;if(intValue==null){System.out.println("int value is null");}if(num==0){System.out.println("int value is 0");} 1. ...
As we’ve already handled the null case, we only need to check whether the result of the expression with the ternary operator is zero. Next, let’s test if this works with our three Integer instances: int n0 = 0; boolean result0 = usingTernaryOperator(n0); assertTrue(result0); boolean...
}if(fieldValue !=null){//只要有一个属性值不为null 就返回false 表示对象不为nullflag =false;break; } }returnflag; } } 测试publicclassCheckObjectIsNullUtilsTest { @TestpublicvoidtestObjectCheck(){ CheckObjectIsNullUtils checkUtils=newCheckObjectIsNullUtils(); User user=newUser();booleanflag1 ...
JVM有专门处理int、reference类型和检测null值的指令: 对boolean、byte、char和short类型的条件分支比较操作,都是使用int类型的比较操作指令; 对long、float和double类型的条件分支比较操作,则先会执行相应类型的比较运算指令(dempg、dempl、fempg、fempl、lemp),然后返回一个整型值到操作数栈中,再执行int类型的条件分...
publicstaticintjustReturn(int x){returnx;} 为了对理想图有一个直观的认识,可以试着可视化它。使用如下JVM参数: -XX:-TieredCompilation:关闭分层编译只使用C2。 -XX:+PrintIdeal:输出Ideal日志。 -XX:PrintIdealGraphFile=ideal.xml:将理想图存储到ideal.xml文件。
final int HELP=1;final int ABOUT=2;final int OUIT=3; public MenuMidlet() {dis = Display.getDisplay(this);menuList = new List("随便游戏",Choice.IMPLICIT,strMenu,null);f = new Form("");alert = new Alert("");alert.setString("欢迎进入游戏");alert.setTimeout(3000);cmdOK = (...
NullPointerException(IntPtr, JniHandleOwnership) A constructor used when creating managed representations of JNI objects; called by the runtime. NullPointerException(String) Constructs a NullPointerException with the specified detail message. Fields Luaskan tabel is_generated (Inherited from Throwabl...
publicclassMain{// Uninitialized variable of reference type will store null until initializedprivatestaticObject emptyObject;// Uninitialized integer is a primitive type so it will store a value (e.g., 0)privatestaticintemptyInt;publicstaticvoidmain(String[] args){// Initialized integer with value...
public class Main { public static void main(String[] args) throws Exception { URL url = new URL("https://api.example.com/data"); HttpURLConnection connection = (HttpURLConnection) url.openConnection(); connection.setRequestMethod("GET"); int responseCode = connection.getResponseCode(); ...