Declare and initialize an array in Java

import javax.swing.*;  
public class FirstSwingExample {  
public static void main(String[] args) {  
JFrame f=new JFrame();//creating instance of JFrame  
          
JButton b=new JButton("click");//creating instance of JButton  
b.setBounds(130,100,100, 40);//x axis, y axis, width, height  
          
f.add(b);//adding button in JFrame  
          
f.setSize(400,500);//400 width and 500 height  
f.setLayout(null);//using no layout managers  
f.setVisible(true);//making the frame visible  
}  
}  

List<String> songList = new ArrayList<>();
songList.add("Some song"); //Repeat until satisfied

System.out.println("\n\tWelcome! Please choose a song!");
String songChoice = scan.nextLine();
while (!songList.contains(songChoice)) {
    //Do stuff when input is not a recognised song
}

private boolean oneQueenPerRow() {
    int foundQueens;
    for (int i = 0; i < board.length; i++) {
        foundQueens = 0;//each loop is a checked row
        for (int j = 0; j < board.length; j++) {
            if (board[i][j] == QUEEN)
                foundQueens++;
        }
        if (foundQueens > 1) return false;
    }
    return true;
}

import java.util.Stack;

/**
 * Java Program to implement a binary search tree. A binary search tree is a
 * sorted binary tree, where value of a node is greater than or equal to its
 * left the child and less than or equal to its right child.
 * 
 * @author WINDOWS 8
 *
 */
public class BST {

    private static class Node {
        private int data;
        private Node left, right;

        public Node(int value) {
            data = value;
            left = right = null;
        }
    }

    private Node root;

    public BST() {
        root = null;
    }

    public Node getRoot() {
        return root;
    }

    /**
     * Java function to check if binary tree is empty or not
     * Time Complexity of this solution is constant O(1) for
     * best, average and worst case. 
     * 
     * @return true if binary search tree is empty
     */
    public boolean isEmpty() {
        return null == root;
    }

    
    /**
     * Java function to return number of nodes in this binary search tree.
     * Time complexity of this method is O(n)
     * @return size of this binary search tree
     */
    public int size() {
        Node current = root;
        int size = 0;
        Stack<Node> stack = new Stack<Node>();
        while (!stack.isEmpty() || current != null) {
            if (current != null) {
                stack.push(current);
                current = current.left;
            } else {
                size++;
                current = stack.pop();
                current = current.right;
            }
        }
        return size;
    }


    /**
     * Java function to clear the binary search tree.
     * Time complexity of this method is O(1)
     */
    public void clear() {
        root = null;
    }

}

Map<String, String> map = ...
for (Map.Entry<String, String> entry : map.entrySet()) {
    System.out.println(entry.getKey() + "/" + entry.getValue());
}

String[][] deepArray = new String[][] {{"John", "Mary"}, {"Alice", "Bob"}};
System.out.println(Arrays.toString(deepArray));
//output: [[Ljava.lang.String;@106d69c, [Ljava.lang.String;@52e922]
System.out.println(Arrays.deepToString(deepArray));

$test = collect([
   [
     'key1' => ['value1' => 5, 'value2' => 3, 'value3' => 0],
     'key2' => ['value1' => 1, 'value2' => 6, 'value3' => 2],
     'key3' => ['value1' => 0, 'value2' => 0, 'value3' => 1],
   ],

   [
     'key1' => ['value1' => 3, 'value2' => 1, 'value3' => 7],
     'key2' => ['value1' => 1, 'value2' => 3, 'value3' => 2],
     'key3' => ['value1' => 1, 'value2' => 6, 'value3' => 1],
   ],

   [
     'key1' => ['value1' => 2, 'value2' => 3, 'value3' => 9],
     'key2' => ['value1' => 3, 'value2' => 8, 'value3' => 3],
     'key3' => ['value1' => 1, 'value2' => 0, 'value3' => 6],
   ]
]);
$mappedCollection = collect($test->first())->keys()->mapWithKeys(function($item,$key) use($test){
   return[
      $item => $test->map(function ($mapItem, $mapKey) use($item) {         
         return $mapItem[$item];
      })
   ];
})->mapWithKeys(function($item,$key){
   $eachLine = collect($item->first())->keys()->mapWithKeys(function($mapItem) use($item){
      return[ $mapItem => $item->sum($mapItem)  ];
   });       
   return [$key =>  $eachLine];
})->all();

dd($mappedCollection);

import java.util.ArrayDeque;
import java.util.Arrays;
import java.util.Queue;

class Pair {
    int x, y;

    public Pair(int x, int y) {
        this.x = x;
        this.y = y;
    }
}

class FloodFill
{
    // Below arrays details all 8 possible movements
    private static final int[] row = { -1, -1, -1, 0, 0, 1, 1, 1 };
    private static final int[] col = { -1, 0, 1, -1, 1, -1, 0, 1 };

    // check if it is possible to go to pixel (x, y) from
    // current pixel. The function returns false if the pixel
    // has different color or it is not a valid pixel
    public static boolean isSafe(char[][] M, int m, int n,
                                int x, int y, char target)
    {
        return x >= 0 && x < m && y >= 0 && y < n
                && M[x][y] == target;
    }

    // Flood fill using BFS
    public static void floodfill(char[][] M, int x, int y, char replacement)
    {
        int m = M.length;
        int n = M[0].length;

        // create a queue and enqueue starting pixel
        Queue<Pair> q = new ArrayDeque<>();
        q.add(new Pair(x, y));

        // get target color
        char target = M[x][y];

        // run till queue is not empty
        while (!q.isEmpty())
        {
            // pop front node from queue and process it
            Pair node = q.poll();

            // (x, y) represents current pixel
            x = node.x;
            y = node.y;

            // replace current pixel color with that of replacement
            M[x][y] = replacement;

            // process all 8 adjacent pixels of current pixel and
            // enqueue each valid pixel
            for (int k = 0; k < row.length; k++)
            {
                // if adjacent pixel at position (x + row[k], y + col[k]) is
                // a valid pixel and have same color as that of current pixel
                if (isSafe(M, m, n, x + row[k], y + col[k], target))
                {
                    // enqueue adjacent pixel
                    q.add(new Pair(x + row[k], y + col[k]));
                }
            }
        }
    }

    public static void main(String[] args)
    {
        // matrix showing portion of the screen having different colors
        char[][] M = {
            "YYYGGGGGGG".toCharArray(),
            "YYYYYYGXXX".toCharArray(),
            "GGGGGGGXXX".toCharArray(),
            "WWWWWGGGGX".toCharArray(),
            "WRRRRRGXXX".toCharArray(),
            "WWWRRGGXXX".toCharArray(),
            "WBWRRRRRRX".toCharArray(),
            "WBBBBRRXXX".toCharArray(),
            "WBBXBBBBXX".toCharArray(),
            "WBBXXXXXXX".toCharArray()
        };

        // start node
        int x = 3, y = 9;   // target color = "X"

        // replacement color
        char replacement = 'C';

        // replace target color with replacement color
        floodfill(M, x, y, replacement);

        // print the colors after replacement
        for (int i = 0; i < M.length; i++) {
            System.out.println(Arrays.toString(M[i]));
        }
    }
}

import org.json.*;


JSONObject obj = new JSONObject(" .... ");
String pageName = obj.getJSONObject("pageInfo").getString("pageName");

JSONArray arr = obj.getJSONArray("posts");
for (int i = 0; i < arr.length(); i++)
{
    String post_id = arr.getJSONObject(i).getString("post_id");
    ......
}

class Main
{
	static int totalWeight = 0;
    // A class to represent a graph edge
    class Edge implements Comparable<Edge>
    {
        int src, dest, weight;
 
        // Comparator function used for sorting edges based on
        // their weight
        public int compareTo(Edge compareEdge)
        {
            return this.weight-compareEdge.weight;
        }
    };
 
    // A class to represent a subset for union-find
    class subset
    {
        int parent, rank;
    };
 
    int V, E;	// V-> no. of vertices & E->no.of edges
    Edge edge[]; // collection of all edges
 
    // Creates a graph with V vertices and E edges
    Main(int v, int e)
    {
        V = v;
        E = e;
        edge = new Edge[E];
        for (int i=0; i<e; ++i)
            edge[i] = new Edge();
    }
 
    // A utility function to find set of an element i
    // (uses path compression technique)
    int find(subset subsets[], int i)
    {
        // find root and make root as parent of i (path compression)
        if (subsets[i].parent != i)
            subsets[i].parent = find(subsets, subsets[i].parent);
 
        return subsets[i].parent;
    }
 
    // A function that does union of two sets of x and y
    // (uses union by rank)
    void Union(subset subsets[], int x, int y)
    {
        int xroot = find(subsets, x);
        int yroot = find(subsets, y);
 
        // Attach smaller rank tree under root of high rank tree
        // (Union by Rank)
        if (subsets[xroot].rank < subsets[yroot].rank)
            subsets[xroot].parent = yroot;
        else if (subsets[xroot].rank > subsets[yroot].rank)
            subsets[yroot].parent = xroot;
 
        // If ranks are same, then make one as root and increment
        // its rank by one
        else
        {
            subsets[yroot].parent = xroot;
            subsets[xroot].rank++;
        }
    }
 
    // The main function to construct MST using Kruskal's algorithm
    void KruskalMST()
    {
        Edge result[] = new Edge[V];  // Tnis will store the resultant MST
        int e = 0;  // An index variable, used for result[]
        int i = 0;  // An index variable, used for sorted edges
        for (i=0; i<V; ++i)
            result[i] = new Edge();
 
        // Step 1:  Sort all the edges in non-decreasing order of their
        // weight.  If we are not allowed to change the given graph, we
        // can create a copy of array of edges
        Arrays.sort(edge);
 
        // Allocate memory for creating V ssubsets
        subset subsets[] = new subset[V];
        for(i=0; i<V; ++i)
            subsets[i]=new subset();
 
        // Create V subsets with single elements
        for (int v = 0; v < V; ++v)
        {
            subsets[v].parent = v;
            subsets[v].rank = 0;
        }
 
        i = 0;  // Index used to pick next edge
 
        // Number of edges to be taken is equal to V-1
        while (e < V - 1)
        {
            // Step 2: Pick the smallest edge. And increment the index
            // for next iteration
            Edge next_edge = new Edge();
            next_edge = edge[i++];
 
            int x = find(subsets, next_edge.src);
            int y = find(subsets, next_edge.dest);
 
            // If including this edge does't cause cycle, include it
            // in result and increment the index of result for next edge
            if (x != y)
            {
                result[e++] = next_edge;
                Union(subsets, x, y);
            }
            // Else discard the next_edge
        }
        int totalMSTWeight = 0;
        


        
        for (i = 0; i < e; ++i) {
        		totalMSTWeight += result[i].weight;
        }
//        System.out.println("total " + totalWeight);
//        System.out.println("MST " + totalMSTWeight);
        System.out.println(totalWeight - totalMSTWeight);
    }
 
    // Driver Program
    public static void main (String[] args) throws Exception
    {
    		BufferedReader br = new BufferedReader (new InputStreamReader(System.in));
    		String in = br.readLine();
    		
    		while (!in.equals("0 0")) {
    			totalWeight = 0;
    			String [] split = in.split(" ");
        		int V = Integer.parseInt(split[0]);
        		int E = Integer.parseInt(split[1]);

            Main graph = new Main(V, E);
            
            for (int i=0; i<E; i++) {
            		in = br.readLine();
            		//System.out.println("split2: " + in);
            		String [] split2 = in.split(" ");
            		int a = Integer.parseInt(split2[0]);
            		int b = Integer.parseInt(split2[1]);
            		int c = Integer.parseInt(split2[2]);
            		
            		graph.edge[i].src = a;
            		graph.edge[i].dest = b;
            		graph.edge[i].weight = c;
            		
            		totalWeight += c;
            		//System.out.println("source: "+a+", dest: " + b + " weight: "+ c);
            }
            graph.KruskalMST();
            in = br.readLine();
    		}
    }
}

    AlarmManager alarmManager;

public class LocalDatabase extends SQLiteOpenHelper {
         
    private static final String mDatabaseName = "LocalDatabase";
    private static final int mDatabaseVersion = 1;

public LocalDatabase(Context context) {
        super(context, mDatabaseName, null, mDatabaseVersion);
        SQLiteDatabase db = this.getWritableDatabase();
    }      

}

 public void sort(int array[]) { 
     for (int i = 1; i < array.length; i++) { 
          int key = array[i]; 
          int j = i - 1; 
          while (j >= 0 && array[j] > key) { 
              array[j + 1] = array[j]; 
              j = j - 1; 
          } 
          array[j + 1] = key; 
      } 
 }

// IntendedActivity - the file you wish to open
// CurrentActivity - the file where this code is placed  

Intent intent = new Intent (this, IntendedActivity.class);
    CurrentActivity.this.startActivity(intent);

for(int i = 0; i < 108; i++) {
System.out.println('Jai Shri Ram!');
}