Java is always pass-by-value. Unfortunately, when we deal with objects we are really dealing with object-handles called references which are passed-by-value as well. This terminology and semantics easily confuse many beginners. It goes like this: public static void main(String[] args) { Dog aDog = new Dog(“Max”); Dog oldDog = aDog; // we pass the object … Read more
== tests for reference equality (whether they are the same object). .equals() tests for value equality (whether they are logically “equal”). Objects.equals() checks for null before calling .equals() so you don’t have to (available as of JDK7, also available in Guava). Consequently, if you want to test whether two strings have the same value you … Read more
When you declare a reference variable (i.e., an object), you are really creating a pointer to an object. Consider the following code where you declare a variable of primitive type int: int x; x = 10; In this example, the variable x is an int and Java will initialize it to 0 for you. When … Read more