I created an enum array like this:
enum MyEnums {
FIRST, SECOND, THIRD, FOURTH;
}
public class MyEnumsTest {
public static void main(String[] args) throws Exception {
MyEnums[] myEnums = new MyEnums[4];
for(int i = 0; i< myEnums.length; i++) {
System.out.println(myEnums[i]);
}
}
}
But why is the output null, null, null and null? And how can I get the element by myEnums[i].FIRST?
What you're doing here is creating an array of MyEnums, and the default value is null (you haven't set the values in the array).
If you wanted to print out the enum values you can use the values() method:
for(MyEnums en : MyEnums.values()) {
System.out.println(en);
}
or (more like your original code)
for(int i = 0; i < MyEnums.values().length; i++) {
System.out.println(MyEnums.values()[i]);
}
This prints:
FIRST
SECOND
THIRD
FOURTH
public static final which means they belong to the enum/class itself (not the instance). Therefore you can access them even if an object is null. Take for example a class Test with 1 member public static final String NAME = "a";, you can create a variable like this Test t = null; but you can still call t.NAME and it will return a.