ADDITIONAL SYSTEM INFORMATION :
Windows 11, Java 17

A DESCRIPTION OF THE PROBLEM :
please run this and check the output

public static List<List<Integer>> printAllCombination2(int[] arr) { //1,2,3,4

if(arr == null || arr.length<1)
return new ArrayList<>();
List<List<Integer>> intlist = new ArrayList<>();

for(int i=0; i<arr.length; i++) {

int j=i;

List<Integer> ilist = new ArrayList<>();

while(j<arr.length) {
ilist.add(arr[j]);
intlist.add(ilist);
j++;
}

}

return intlist;

}



STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
run the code which has provided in the description, list object is behaving differently

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
[[1], [1, 2], [1, 2, 3], [1, 2, 3, 4], [2], [2, 3], [2, 3, 4], [3], [3, 4], [4]]
ACTUAL -
[[1, 2, 3, 4], [1, 2, 3, 4], [1, 2, 3, 4], [1, 2, 3, 4], [2, 3, 4], [2, 3, 4], [2, 3, 4], [3, 4], [3, 4], [4]]

---------- BEGIN SOURCE ----------
import java.util.ArrayList;
import java.util.List;

public class TestProgram {


   
   public static List<List<Integer>> printAllCombination2(int[] arr) { //1,2,3,4

if(arr == null || arr.length<1)
return new ArrayList<>();
List<List<Integer>> intlist = new ArrayList<>();

for(int i=0; i<arr.length; i++) {

int j=i;

List<Integer> ilist = new ArrayList<>();

while(j<arr.length) {
ilist.add(arr[j]);
intlist.add(ilist);
j++;
}

}

return intlist;

}
   

public static void main(String[] args) {

int[] arr = {1,2,3,4};

System.out.println(" combinations :::: "+printAllCombination2(arr));
}


}

---------- END SOURCE ----------

CUSTOMER SUBMITTED WORKAROUND :
import java.util.ArrayList;
import java.util.List;

public class TestProgram {


   public static List<List<Integer>> printAllCombination1(int[] arr) {

if(arr == null || arr.length<1)
return new ArrayList<>();
List<List<Integer>> intlist = new ArrayList<>();

for(int i=0; i<arr.length; i++) { //1,2,3,4

int j=i;

List<Integer> ilist = new ArrayList<>();

while(j<arr.length) {
ilist.add(arr[j]);
List<Integer> nlist = new ArrayList<>(ilist);
intlist.add(nlist);
j++;
}

}

return intlist;

}
   
   

public static void main(String[] args) {

int[] arr = {1,2,3,4};

System.out.println(" combinations :::: "+printAllCombination1(arr));
}


}

FREQUENCY : always