How to delete last element in array and put new in front?

I have a question concerning Java. I started up new to Java and my google search brought many results but non was the final help.
I created a class to track historical information. I have different values for different days and need to update them un a regular basis. I want to keep track of the last 30 days and created an array with 30 elements. When I call my 'shift' function I want to drop the last n elements and put zeros in front. Here is a minial example for 5 days:

public class Testclass {

    private int[] histInfo;

    public Element()
    {
        this.histInfo = new int[5];
    }

    public void shift_histInfo(long m)
    {
        //do magic 
    }
}

What I want shift to do is

INPUT:
histInfo = [50,21,1,45,901]

OPERATION:
shift_histInfo(2);

RESULT:
histInfo = [0,0,50,21,1]

I am thankfull for every kind of help you can support as well for thought-provoking impulses if you think that there is a way more elegant or efficient way.

Best

Unless there are very tight performance constraints using the standard Collection classes will get the job done. Have a look at java.util.LinkedList.

As a programming exercise you might consider creating a ring buffer. The idea being to avoid copying the array on every insertion.

Keep a oldestIndex value.

When writing simply replace item[oldestIndex] and increment oldestIndex.

To iterate you start at oldestIndex and use an increment method to deal with wrapping round to the start of the array.

int nextIndex(int current) {
   return (current + 1) % arrayLength;
}

Writing a nice encapsulating class to hide all this would be a good exercise.

You can try this :

public static void shift_histInfo(long m)
{
    int[] myIntArray = {50,21,1,45,901};
    int[] myIntArray2 = {50,21,1,45,901};

    for (int j=0 ;j< myIntArray.length ; j++){
        int temp = (int) (j+m);
        if (temp >= myIntArray.length){
            temp = temp - myIntArray.length;
            myIntArray2[temp] = 0;
        } else {
            myIntArray2[temp] = myIntArray[j];
        }

    }
    for (int j=0 ;j< myIntArray2.length ; j++){
        System.out.println(myIntArray2[j]);
    }

}

Output :

when shift_histInfo(2) ,

[0,0,50,21,1]

    int[] array={1,2,3,4,5,6};
    int removelength=2;
	int e=1;
	while(e<=removelength) {
		for(int i=1;i<array.length;i++)
		array[array.length-i]=array[array.length-i-1];
		e++;
	}
	
	for(int i=0;i<removelength;i++) {
		array[i]=0;
	}
    for(int g:array)
    {
      System.out.print(g);
    }

For constraints that you wanted, although I did initialise the data in the same method instead of Element(). I don't know why the parameter is of type long so I left it and made an int local variable.

All it does is copy the index value over to the new array starting at m then increments/iterates until the end of the array.

You can also make the method return type int[] and then simply return changedInfo array. Instead of histInfo = changedInfo.clone();

private int[] histInfo;

    public void shift_histInfo(long m) {
        int n = (int) m;
        this.histInfo = new int[]{1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15,1, 2, 3, 4, 5, 6, 7, 8, 9,10,11,12,13,14,15};

        int length = this.histInfo.length;
        int[] changedInfo = new int[length];

        if (length - n >= 0) System.arraycopy(histInfo, 0, changedInfo, n + 0, length - n); //Edit: shortened to one line.

        histInfo = changedInfo.clone();
        System.out.println("Remove: " + n + " - " + Arrays.toString(changedInfo) + "\n");

    }
    public static void main(String[] args) {
        Main main = new Main();
        main.shift_histInfo(0);
        main.shift_histInfo(30);
        main.shift_histInfo(1);
        main.shift_histInfo(15);
        main.shift_histInfo(29);
    }

println:

Remove: 0 - [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

Remove: 30 - [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0]

Remove: 1 - [0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14]

Remove: 15 - [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15]

Remove: 29 - [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1]