11/9/2023 0 Comments Java array initializerSuppose we have an array of String as: String name = new String Suppose we have an array of double type as: double dArr = new double String Array Initialization in Java (Reference type Arrays)Īn array with primitive type elements contains values of that primitive type, whereas elements of a reference type array contain the reference to objects. String name = new String // A local array variable ("\nArray initialization of reference type:") Initial values for bArr elements are displayed inside the constructor. ("\nArray initialization of boolean type:") Int intArr = new int // A local array variable. Print the initial value for elements of the instance variable bArr. Private final boolean bArr = new boolean // An instance variable. Let’s take a simple example program where we will see the default array initialization for instance and local variables. All 50 elements of the Employee array are initialized to null. Another example of a class type array. strArr and strArr are initialized to null. An example of class type (means reference type) array. bArr and bArr are initialized to false. The following snippet of code are examples of the array initialization: // intArr, intArr, intArr, and intArr are initialized to zero by default. Array elements of class type are initialized to null. When an array is created, the individual elements of an array are automatically initialized with the default value.įor example, the elements of a numeric array are initialized to zero, boolean array elements to false, and char elements to ‘\u0000’. Default Initialization of Array Elements in Java The length of array object is initialized with the value of length of array that is 10 in this case.ĭuring array initialization, the value of array elements is directly assigned to each array element in the heap memory, as shown in the above figure. In this case, elements of int type are initialized with default value 0. The array object is dynamically allocated in the heap memory with the help of new operator and its memory location is assigned to “num” array reference as shown in the above figure.Īt the time of array object creation, each element of the array is automatically initialized with its default value. The name of an array, num is a reference variable pointed to an object that is stored in the stack memory. The below figure shows how primitive type array num declared and created in the above program has been stored in memory. How Primitive Type Array Objects are stored in Memory? The index for the last element of an array is the size (length) of array minus 1 (i.e. The index for the first element is 0, the second element 1, the third element 2, and so on.Īrray indices are known as zero-based indexing. Java creates an array starting with the index of 0 and ends with a value one less than the size specified. Java throws a runtime exception to refer to a non-existing element of an array.įor example, using num in the above code will throw a runtime exception because num has the length of 10 and num refers to the eleventh element which is non-existing. The size (length) of the array must be the same as the number of values passed in the array initialization list. The above code creates an array of 10 elements and initializes its values 20, 30, 40, and so on. Num = 300 // Assign 300 to the tenth element of num. Num = 30 // Assign 30 to the second element of num. Num = 20 // Assign 20 to the first element of num. Declaring an array variable, creating an array, and assigning the reference of the array to the variable. The general syntax to initialize elements of array when we declare an array or when we create an array object using the new operator is as follows: arrayname = value įor example, the following code initializes values to the various positions in the array. This process is called initialization of array in Java. Once the array is created, the next step is to put the elements (or values) into the array created at compile time.
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