How do you declare and instantiate Java class instances?

"Once we have defined our class and its constructors, we can create and use instances of it. Just as with regular variables, we need to declare instances of a class by providing the type and a variable name. For example:\n\n1 Student s = null;\n\n2 Student t = null;\n\nBoth of these declarations are simply just reference variables. They may refer to an instance of the class Student, but we have initialized them to null. To make these variables refer to valid instances, we invoke a constructor by using the new keyword and providing arguments to the constructor.\n\n1 Student s = new Student(\"Alan\", \"Turing\", 1234, 3.4);\n\n2 Student t = new Student(\"Margaret\", \"Hamilton\", 4321, 3.9);\n\nThe process of creating a new instance by invoking a constructor is referred to as instantiation."