Boxing is the process of putting a primitive value into an analogous object, such as creating an Integer
to hold an int
value. Unboxing is the process of retrieving the primitive value from such an object.
Since the original value is unchanged during boxing and unboxing, there's no point in doing either when not needed. This also applies to autoboxing and auto-unboxing (when Java implicitly handles the primitive/object transition for you).
public void examineInt(int a) { //... } public void examineInteger(Integer a) { // ... } public void func() { int i = 0; Integer iger1 = Integer.valueOf(0); double d = 1.0; int dIntValue = new Double(d).intValue(); // Noncompliant examineInt(new Integer(i).intValue()); // Noncompliant; explicit box/unbox examineInt(Integer.valueOf(i)); // Noncompliant; boxed int will be auto-unboxed examineInteger(i); // Compliant; value is boxed but not then unboxed examineInteger(iger1.intValue()); // Noncompliant; unboxed int will be autoboxed }
public void examineInt(int a) { //... } public void examineInteger(Integer a) { // ... } public void func() { int i = 0; Integer iger1 = Integer.valueOf(0); double d = 1.0; int dIntValue = (int) d; examineInt(i); examineInteger(i); examineInteger(iger1); }