initializing a boolean array in java

Question

I have this code

public static Boolean freq[] = new Boolean[Global.iParameter[2]];
freq[Global.iParameter[2]] = false;

could someone tell me what exactly i'm doing wrong here and how would i correct it? I just need to initialize all the array elements to Boolean false. thank you

Answer 1

The array will be initialized to false when you allocate it.

All arrays in Java are initialized to the default value for the type. This means that arrays of ints are initialised to 0, arrays of booleans are initialised to false and arrays of reference types are initialised to null.

You can find more details here.

Answer 2

public static Boolean freq[] = new Boolean[Global.iParameter[2]];

Global.iParameter[2]:

It should be const value

Answer 3

They will be initialized to false by default. In Java arrays are created on heap and every element of the array is given a default value depending on its type. For boolean data type the default value is false.

Answer 4

I just need to initialize all the array elements to Boolean false.

Either use boolean[] instead so that all values defaults to false:

boolean[] array = new boolean[size];

Or use Arrays#fill() to fill the entire array with Boolean.FALSE:

Boolean[] array = new Boolean[size];
Arrays.fill(array, Boolean.FALSE);

Also note that the array index is zero based. To learn more about arrays in Java, consult this Sun basic tutorial.

Answer 5

Arrays in Java start indexing at 0. So in your example you are referring to an element that is outside the array by one.

It should probably be something like freq[Global.iParameter[2]-1]=false;

You would need to loop through the array to initialize all of it, this line only initializes the last element.

Actually, I'm pretty sure that false is default for booleans in Java, so you might not need to initialize at all.

Best Regards