It depends on the scope where you declare the variable. For instance, local variables don’t have default values
in which case you will have to assign null manually, where as in case of instance variables assigning null is redundant since instance variables get default values.
public class Test {
Object propertyObj1;
Object propertyObj2 = null; // assigning null is redundant here as instance vars get default values
public void method() {
Object localVariableObj1;
localVariableObj1.getClass(); // illegal, a compiler error comes up as local vars don't get default values
Object localVariableObj2 = null;
localVariableObj2.getClass(); // no compiler error as localVariableObj2 has been set to null
propertyObj1.getClass(); // no compiler error
propertyObj2.getClass(); // no compiler error
}
}