Java has fewer quirks compared to C++, but sometimes I do come across surprises.
A code like following will fail to compile since you are trying to initialize a variable with an uninitialized variable.
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| public class Sample {
private final String mField1;
private final String mField2 = mField1 + " two";
private Sample(String field1) {
mField1 = field1;
}
}
|
But if instead of directly referencing mField1, you reference indirectly via a getter method code will compile, and mField2 will get null value for mField1.
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| public class Sample {
private final String mField1;
private final String mField2 = getField1() + " two";
private Sample(String field1) {
mField1 = field1;
}
private String getField1() {
return mField1;
}
private String getField2() {
return mField2;
}
public static void main (String[] args) {
Sample sample = new Sample("one");
// prints "Field 1 is one"
System.out.println("Field 1 is " + sample.getField1());
// prints "Field 2 is null two"!!!
System.out.println("Field 2 is " + sample.getField2());
}
}
|
