JAVA 8 PROGRAMS

 Program to remove duplicate elements from String?

import java.util.Arrays;

import java.util.List;

import java.util.Map;

import java.util.function.Function;

import java.util.stream.Collectors;

public class DuplicateElementsString {

public static void main(String[] args) {

String s="javalanguage";

List<String> duplicateElements=Arrays.stream(s.split(""))

.collect(Collectors.groupingBy(Function.identity(),Collectors.counting()))

.entrySet().stream().filter(x->x.getValue()>1)

.map(Map.Entry::getKey).collect(Collectors.toList());

System.out.println(duplicateElements);

List<String> uniqueElements=Arrays.stream(s.split(""))

.collect(Collectors.groupingBy(Function.identity(),Collectors.counting()))

.entrySet().stream().filter(x->x.getValue()==1)

.map(Map.Entry::getKey).collect(Collectors.toList());

System.out.println(uniqueElements);

}

}

 Program to print Even Numbers?

import java.util.Arrays;

import java.util.List;

public class EvenNumbersUsingStreams {

public static void main(String[] args) {

List<Integer> list=Arrays.asList(10,20,15,12,19,17);

list.stream().filter(n->n%2==0).forEach(System.out::println);

}

}

 Program to find duplicate elements in String?

import java.util.Arrays;

import java.util.HashSet;

import java.util.List;

import java.util.Set;

public class FindDuplicateElements {

public static void main(String args[])

{

List<Integer> list=Arrays.asList(10,20,12,13,12,20,10,90,70);

Set<Integer> set=new HashSet();

list.stream()

    .filter(n->!set.add(n))

    .forEach(System.out::println);

}

}

 Program to find find first element?

import java.util.Arrays;

import java.util.List;

public class FindFirstElement {

public static void main(String[] args) {

List<Integer> list=Arrays.asList(1,2,3,4,5);

list.stream().findFirst().ifPresent(System.out::println);

}

}

 Program to find first Non Repeated Element  in String?

import java.util.Arrays;

import java.util.LinkedHashMap;

import java.util.function.Function;

import java.util.stream.Collectors;

public class FirstNonRepeatedElement {

public static void main(String[] args) {

String s="javajavalang";

String firstNonrepeatedChar=Arrays.stream(s.split(""))

.collect(Collectors.groupingBy(Function.identity(),LinkedHashMap::new,Collectors.counting()))

.entrySet().stream().filter(x->x.getValue()==1)

.findFirst().get().getKey();

System.out.println(firstNonrepeatedChar);

}

}

 Program to find max value?

import java.util.Arrays;

import java.util.List;

public class MaxValue {

public static void main(String[] args) {

List<Integer> list=Arrays.asList(10,2,3,30,7,8);

int max=list.stream().max(Integer::compare).get();

System.out.println(max);

}

}

 Program to display numbers starting with 1?

import java.util.Arrays;

import java.util.List;

public class NumbersStartingWith1 {

public static void main(String[] args) {

List<Integer> list=Arrays.asList(10,20,12,13,30,40);

list.stream()

    .map(s->s+"") //converts integer to String

    .filter(s->s.startsWith("1"))

    .forEach(System.out::println);

}

}

 Program to find occurance of each char in a String?

import java.util.Arrays;

import java.util.List;

import java.util.Map;

import java.util.function.Function;

import java.util.stream.Collectors;

public class OccuranceOfEachChar {

public static void main(String[] args) {

String s="java";

//convert string to array

//String str[]=s.split("");

//System.out.println(Arrays.toString(str));

Map<String,List<String>> result=Arrays.stream(s.split("")).collect(Collectors.groupingBy(s1->s1));

System.out.println(result); //{a=[a, a], v=[v], j=[j]}

Map<String,Long> charCount=Arrays.stream(s.split("")).collect(Collectors.groupingBy(Function.identity(),Collectors.counting()));

System.out.println(charCount);//{a=2, v=1, j=1}

}

}

Program to find 2nd Highest number in array?

import java.util.Arrays;

import java.util.Comparator;

public class SecondHighestNumberArray {

public static void main(String[] args) {

int nums[]= {3,1,10,7,5};

Integer secondHighest=Arrays.stream(nums).boxed().sorted(Comparator.reverseOrder()).skip(1).findFirst().get();

System.out.println(secondHighest);

}

}

Program to find total number of elements?

import java.util.Arrays;

import java.util.List;

public class TotalNumberofElements {

public static void main(String[] args) {

List<Integer> list=Arrays.asList(1,2,3,4,5);

long count=list.stream().count();

System.out.println(count);

}

}