Maximum Sum Submatrix Algorithm:

Kadane Algorithm(O(n)):

public int maxSubArraySum(int[] arr) {
    int maxSoFar = arr[0];
    int maxEndingHere = arr[0];

    for (int i = 1; i < arr.length; i++) {
 
        maxEndingHere = Math.max(arr[i], maxEndingHere + arr[i]);

  
        maxSoFar = Math.max(maxSoFar, maxEndingHere);
    }

    return maxSoFar;
}

DP Bottm-up approach (O(n^2)):

    static int maxSum(int arr[]){
        int dp[][] = new int[arr.length][arr.length];
        
 
        for (int i = 0; i < dp.length; i++) {
            dp[i][i]=arr[i];
            for (int j = i+1; j < dp.length; j++) {
                dp[i][j]=Math.max(arr[j],dp[i][j-1]+arr[j]);
                
            }
        }
  
        return dp[0][arr.length-1];
    }

اتصال به mongodb در جاوا با استفاده از فایل کانفیگ

package org.project..database;


import com.mongodb.client.*;
import org.bson.Document;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Properties;

public class MongoDBHandler {
    private MongoClient mongoClient;
    private MongoDatabase database;
    private MongoCollection<Document> collection;

    public MongoDBHandler(String configFilePath) {
        try {
            Properties properties = new Properties();
            properties.load(new FileInputStream(configFilePath));
            System.out.println(properties);
            String host = properties.getProperty("remote_host");
            int port = Integer.parseInt(properties.getProperty("remote_port"));
            String dbName = properties.getProperty("remote_database");
            String username = properties.getProperty("remote_user");
            String password = properties.getProperty("remote_password");
            String collectionName = properties.getProperty("remote_collection");

            String uri = "mongodb://" + username + ":" + password + "@" + host + ":" + port + "/" + dbName;
            mongoClient = MongoClients.create(uri);

            database = mongoClient.getDatabase(dbName);
            collection = database.getCollection(collectionName);

        } catch (IOException e) {
            e.printStackTrace();
        }
        //System.exit(0);
    }

    public void insertDocument(Document document) {
        collection.insertOne(document);
    }

    public FindIterable<Document> readDocuments() {
        return collection.find();
    }

    public long countDocuments() {
        return collection.countDocuments();
    }

    public void updateDocument(Document query, Document update) {
        collection.updateOne(query, new Document("$set", update));
    }

    public void deleteDocument(Document query) {
        collection.deleteOne(query);
    }

    public MongoCollection<Document> getCollection() {
        return collection;
    }
}

فایل کانفیگ :

remote_host = localhost
remote_database = java
remote_user = parsa
remote_password = kav
remote_port = 27020
remote_collection = users

موجودیت ضعیف در Hibernate
مثال پیاده سازی دفترچه تلفن