We can change the int constants value inThreadStatesConstantclass but the above program will not throw any exception. Our program might not work as expected but if we change the enum constants, we will get compile time error that removes any possibility of runtime issues. Java Enum Methods No...
* in its enum declaration, where the initial constant is assigned * an ordinal of zero). * * Most programmers will have no use for this method. It is * designed for use by sophisticated enum-based data structures, such * as {@link java.util.EnumSet} and {@link java.util.EnumMap}. ...
publicenumMyEnum{CONSTANT1,CONSTANT2,CONSTANT3} 1. 2. 3. 4. 5. 检查常量是否存在 在确认了枚举的定义后,我们需要检查常量是否存在。如果在代码中直接使用了一个不存在的常量,就会抛出java.lang.IllegalArgumentException: No enum constant异常。 为了避免这个异常,我们可以使用枚举的valueOf()方法来检查常量是...
private final double radius; // in meters Planet(double mass, double radius) { this.mass = mass; this.radius = radius; } private double mass() { return mass; } private double radius() { return radius; } // universal gravitational constant (m3 kg-1 s-2) public static final double G...
toStringin classObject Returns: the name of this enum constant hashCode public final int hashCode() Returns a hash code for this enum constant. Overrides: hashCodein classObject Returns: a hash code for this enum constant. See Also: Object.equals(java.lang.Object),System.identityHashCode(java....
java.lang.RuntimeException java.lang.EnumConstantNotPresentException すべての実装されたインタフェース: Serializable public classEnumConstantNotPresentExceptionextendsRuntimeException アプリケーションが名前によりenum定数にアクセスしようとしたときや、指定された名前の定数を持たないenum型にアクセス...
Returns the Class object corresponding to this enum constant's enum type. C# publicJava.Lang.Class DeclaringClass { [Android.Runtime.Register("getDeclaringClass","()Ljava/lang/Class;","")]get; } Property Value Class the Class object corresponding to this enum constant's enum type ...
以下示例程序旨在说明isEnumConstant()方法: 示例1: // Java program to illustrate//isEnumConstant() methodimportjava.lang.reflect.Field;importjava.time.Month;publicclassGFG{publicstaticvoidmain(String[] args)throwsNoSuchFieldException{// get all declared fields of Month classField[] declaredFields ...
static java.lang.String getLanguageCode(QMapLanguage language) static QMapLanguage valueOf(java.lang.String name) Returns the enum constant of this type with the specified name. static QMapLanguage[] values() Returns an array containing the constants of this enum type, in the order they are...
Java Copy In this example, we’ve defined an enumDaywith two constants:MONDAYandTUESDAY. Each constant is assigned a specific value through the enum’s constructor. The private variablevalueholds the value for each constant. This is just a basic way to use enums with values in Java, but ...