For Loop Performance Test
import java.util.ArrayList;
import java.util.Calendar;
import java.util.List;
public class ForLoopPerformanceTest{
private static List<Integer> list = new ArrayList<Integer>();
private static long startTime;
public static void main(String[] args) {
for (int i = 0; i < 10000000; i++) {
list.add(i);
}
// Java 8 for each
startTime = Calendar.getInstance().getTimeInMillis();
list.forEach(e -> { });
System.out .println("Using java 8 for each :: " +
(Calendar.getInstance().getTimeInMillis() - startTime) + " ms");
// Type 1
startTime = Calendar.getInstance().getTimeInMillis();
for (Integer i : list) { // }
System.out.println("Using For each loop :: " +
(Calendar.getInstance().getTimeInMillis() - startTime) + " ms");
// Type 2
startTime = Calendar.getInstance().getTimeInMillis();
for (int j = 0; j < list.size(); j++) { // }
System.out.println("Using collection.size() :: " +
(Calendar.getInstance().getTimeInMillis() - startTime) + " ms");
// Type 3
startTime = Calendar.getInstance().getTimeInMillis();
int size = list.size();
for (int j = 0; j < size; j++) { // }
System.out.println("Using [int size = list.size(); int j = 0; j < size ; j++] :: "
+ (Calendar.getInstance().getTimeInMillis() - startTime) + " ms");
}
}
Out Put :-
Using java 8for each :: 122 ms
Using For each loop :: 40 ms
Using collection.size() :: 6 ms
Using [int size = list.size(); int j = 0; j < size ; j++] :: 6 ms
import java.util.Calendar;
import java.util.List;
public class ForLoopPerformanceTest{
private static List<Integer> list = new ArrayList<Integer>();
private static long startTime;
public static void main(String[] args) {
for (int i = 0; i < 10000000; i++) {
list.add(i);
}
// Java 8 for each
startTime = Calendar.getInstance().getTimeInMillis();
list.forEach(e -> { });
System.out .println("Using java 8 for each :: " +
(Calendar.getInstance().getTimeInMillis() - startTime) + " ms");
// Type 1
startTime = Calendar.getInstance().getTimeInMillis();
for (Integer i : list) { // }
System.out.println("Using For each loop :: " +
(Calendar.getInstance().getTimeInMillis() - startTime) + " ms");
// Type 2
startTime = Calendar.getInstance().getTimeInMillis();
for (int j = 0; j < list.size(); j++) { // }
System.out.println("Using collection.size() :: " +
(Calendar.getInstance().getTimeInMillis() - startTime) + " ms");
// Type 3
startTime = Calendar.getInstance().getTimeInMillis();
int size = list.size();
for (int j = 0; j < size; j++) { // }
System.out.println("Using [int size = list.size(); int j = 0; j < size ; j++] :: "
+ (Calendar.getInstance().getTimeInMillis() - startTime) + " ms");
}
}
Out Put :-
Using java 8for each :: 122 ms
Using For each loop :: 40 ms
Using collection.size() :: 6 ms
Using [int size = list.size(); int j = 0; j < size ; j++] :: 6 ms
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