System.out.print("Amit Shekhar");
System.out.println("Amit Shekhar");
print("Amit Shekhar")
println("Amit Shekhar")
String name = "Amit Shekhar";
final String name = "Amit Shekhar";
var name = "Amit Shekhar"
val name = "Amit Shekhar"
String otherName;
otherName = null;
var otherName : String?
otherName = null
if (text != null) {
int length = text.length();
}
text?.let {
val length = text.length
}
// or simply
val length = text?.length
String firstName = "Amit";
String lastName = "Shekhar";
String message = "My name is: " + firstName + " " + lastName;
val firstName = "Amit"
val lastName = "Shekhar"
val message = "My name is: $firstName $lastName"
String text = "First Line\n" +
"Second Line\n" +
"Third Line";
val text = """
|First Line
|Second Line
|Third Line
""".trimMargin()
String text = x > 5 ? "x > 5" : "x <= 5";
val text = if (x > 5)
"x > 5"
else "x <= 5"
final int andResult = a & b;
final int orResult = a | b;
final int xorResult = a ^ b;
final int rightShift = a >> 2;
final int leftShift = a << 2;
val andResult = a and b
val orResult = a or b
val xorResult = a xor b
val rightShift = a shr 2
val leftShift = a shl 2
if (object instanceof Car) {
}
Car car = (Car) object;
if (object is Car) {
}
var car = object as Car
if (object instanceof Car) {
Car car = (Car) object;
}
if (object is Car) {
var car = object // smart casting
}
if (score >= 0 && score <= 300) { }
if (score in 0..300) { }
int score = // some score;
String grade;
switch (score) {
case 10:
case 9:
grade = "Excellent";
break;
case 8:
case 7:
case 6:
grade = "Good";
break;
case 5:
case 4:
grade = "OK";
break;
case 3:
case 2:
case 1:
grade = "Fail";
break;
default:
grade = "Fail";
}
var score = // some score
var grade = when (score) {
9, 10 -> "Excellent"
in 6..8 -> "Good"
4, 5 -> "OK"
in 1..3 -> "Fail"
else -> "Fail"
}
for (int i = 1; i <= 10 ; i++) { }
for (int i = 1; i < 10 ; i++) { }
for (int i = 10; i >= 0 ; i--) { }
for (int i = 1; i <= 10 ; i+=2) { }
for (int i = 10; i >= 0 ; i-=2) { }
for (String item : collection) { }
for (Map.Entry<String, String> entry: map.entrySet()) { }
for (i in 1..10) { }
for (i in 1 until 10) { }
for (i in 10 downTo 0) { }
for (i in 1..10 step 2) { }
for (i in 10 downTo 1 step 2) { }
for (item in collection) { }
for ((key, value) in map) { }
final List<Integer> listOfNumber = Arrays.asList(1, 2, 3, 4);
final Map<Integer, String> keyValue = new HashMap<Integer, String>();
map.put(1, "Amit");
map.put(2, "Ali");
map.put(3, "Mindorks");
// Java 9
final List<Integer> listOfNumber = List.of(1, 2, 3, 4);
final Map<Integer, String> keyValue = Map.of(1, "Amit",
2, "Ali",
3, "Mindorks");
val listOfNumber = listOf(1, 2, 3, 4)
val keyValue = mapOf(1 to "Amit",
2 to "Ali",
3 to "Mindorks")
// Java 7 and below
for (Car car : cars) {
System.out.println(car.speed);
}
// Java 8+
cars.forEach(car -> System.out.println(car.speed));
// Java 7 and below
for (Car car : cars) {
if (car.speed > 100) {
System.out.println(car.speed);
}
}
// Java 8+
cars.stream().filter(car -> car.speed > 100).forEach(car -> System.out.println(car.speed));
cars.forEach {
println(it.speed)
}
cars.filter { it.speed > 100 }
.forEach { println(it.speed)}
void doSomething() {
// logic here
}
void doSomething(int... numbers) {
// logic here
}
fun doSomething() {
// logic here
}
fun doSomething(vararg numbers: Int) {
// logic here
}
int getScore() {
// logic here
return score;
}
fun getScore(): Int {
// logic here
return score
}
// as a single-expression function
fun getScore(): Int = score
int getScore(int value) {
// logic here
return 2 * value;
}
fun getScore(value: Int): Int {
// logic here
return 2 * value
}
// as a single-expression function
fun getScore(value: Int): Int = 2 * value
public class Utils {
private Utils() {
// This utility class is not publicly instantiable
}
public static int getScore(int value) {
return 2 * value;
}
}
class Utils private constructor() {
companion object {
fun getScore(value: Int): Int {
return 2 * value
}
}
}
// another way
object Utils {
fun getScore(value: Int): Int {
return 2 * value
}
}
public class Developer {
private String name;
private int age;
public Developer(String name, int age) {
this.name = name;
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getAge() {
return age;
}
public void setAge(int age) {
this.age = age;
}
@Override
public boolean equals(Object o) {
if (this == o) return true;
if (o == null || getClass() != o.getClass()) return false;
Developer developer = (Developer) o;
if (age != developer.age) return false;
return name != null ? name.equals(developer.name) : developer.name == null;
}
@Override
public int hashCode() {
int result = name != null ? name.hashCode() : 0;
result = 31 * result + age;
return result;
}
@Override
public String toString() {
return "Developer{" +
"name='" + name + '\'' +
", age=" + age +
'}';
}
}
data class Developer(val name: String, val age: Int)
public class Utils {
private Utils() {
// This utility class is not publicly instantiable
}
public static int triple(int value) {
return 3 * value;
}
}
int result = Utils.triple(3);
fun Int.triple(): Int {
return this * 3
}
var result = 3.triple()
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Copyright (C) 2017 MINDORKS NEXTGEN PRIVATE LIMITED
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.