The method java.io.File.renameTo() is used to rename a file or directory. This method requires a single parameter i.e. the name that the file or directory is renamed to and it returns true on the success of the renaming or false otherwise.A program that demonstrates this is given as follows −Example Live Demoimport java.io.File; public class Demo {    public static void main(String[] args) {       try {          File file1 = new File("demo1.txt");          File file2 = new File("demo2.txt");          file1.createNewFile();          file2.createNewFile();         ... Read More

A file can be set to read-only by using the method java.io.File.setReadOnly(). This method requires no parameters and it returns true if the file is set to read-only and false otherwise. The method java.io.File.canWrite() is used to check whether the file can be written to in Java and if not, then the file is confirmed to be read-only.A program that demonstrates this is given as follows −Example Live Demoimport java.io.File; public class Demo {    public static void main(String[] args) {       boolean flag;       try {          File file = new File("demo1.txt");   ... Read More

To disable the warning while connecting to a database in Java, use the below concept −autoReconnect=true&useSSL=falseThe complete syntax is as follows −yourJdbcURL="jdbc:mysql://localhost:yourPortNumber/yourDatabaseName?autoReconnect=true&useSSL=false";Here is the warning message if you do not include “useSSL=false” −Wed Feb 06 18:53:39 IST 2019 WARN: Establishing SSL connection without server's identity verification is not recommended. According to MySQL 5.5.45+, 5.6.26+ and 5.7.6+ requirements SSL connection must be established by default if explicit option isn't set. For compliance with existing applications not using SSL the verifyServerCertificate property is set to 'false'. You need either to explicitly disable SSL by setting useSSL=false, or set useSSL=true and provide truststore ... Read More

You need to use executeQuery() for this. The syntax is as follows −yourPreparedStatementObject=yourConnectionObject.prepareStatement(yourQueryName); yourresultSetObject=yourPreparedStatementObject.executeQuery();Create a table in the database ‘sample’. The query to create a table is as follows −mysql> create table JavaPreparedStatement -> ( -> Id int, -> Name varchar(10), -> Age int -> ); Query OK, 0 rows affected (0.89 sec)Insert some records in the table using insert command. The query is as follows −mysql> insert into JavaPreparedStatement values(1, 'Larry', 23); Query OK, 1 row affected (0.16 sec) mysql> insert into JavaPreparedStatement values(2, ... Read More

To add the JDBC MySQL driver to an Eclipse project, you need to follow the below steps.The first step is as follows:Step1: Create a dynamic web project with some name in Eclipse.Step2: After pressing the Dynamic Web Project, a new window will open. Now give the project name. The screenshot is as follows:After clicking the Finish button, you will get a project structure. The screenshot is as follows:Therefore, I have a project name JDBCJarFiles and in WEB-INF, there is a lib folder. You can add JDBC jar files in lib folder. Now, paste the jar files here. The screenshot is as ... Read More

To insert a record in the table using PreparedStatement in Java, you need to use below syntax to insert records. The syntax is as follows −String anyVariableName= "INSERT INTO yourTableName(yourColumnName1, yourColumnName2, yourColumnName3, .........N)" + "VALUES (?, ?, ?, ..............N)";Now use the PreparedStatement object to set the value for all columns. The syntax is as follows −PreparedstatementObject = con.prepareStatement(query); PreparedstatementObject .setXXX(1, yourValue); PreparedstatementObject .setXXX(2, yourValue); PreparedstatementObject .setXXX(3, yourValue); . . . NThe above prepared statement will solve your problem. Now first create a table in MySQL. The query to create a table is as follows −mysql> create table CourseDemo -> ( ... Read More

To get the column name on the result set, you need to use getMetaData() method. The prototype of getMetadata() is as follows −ResultSetMetaData getMetaData throws SQLException;Create a MySQL table with 5 column names. The query to create a table is as follows −mysql> create table javagetallcolumnnames    -> (    -> Id int NOT NULL AUTO_INCREMENT,    -> Name varchar(20),    -> Age int,    -> Salary float,    -> Address varchar(100),    -> PRIMARY KEY(Id)    -> ); Query OK, 0 rows affected (1.34 sec)The following is the Java code that gets the column name on ResultSet. The code ... Read More

A file or directory can be deleted on termination of the program i.e. after the virtual machine terminates using the method java.io.File.deleteOnExit(). This method requires no parameters and it does not return a value.A program that demonstrates this is given as follows −Example Live Demoimport java.io.File; public class Demo {    public static void main(String[] args) {       try {          File file = new File("demo1.txt");          file.createNewFile();          System.out.println("File: " + file);          file.deleteOnExit();       } catch(Exception e) {          e.printStackTrace(); ... Read More

The contents of a directory can be obtained using the method java.io.File.listFiles(). This method requires no parameters and it returns the abstract path names that specify the files and directories in the required directory.A program that demonstrates this is given as follows −Exampleimport java.io.File; public class Demo {    public static void main(String[] args) {       File directory = new File("C:\JavaProgram");       File[] contents = directory.listFiles();       for (File c : contents) {          if(c.isFile())             System.out.println(c + " is a file");         ... Read More

The name of the specified file or directory can be obtained using the method java.io.File.getName(). The getName() returns the name of the file or the directory and it requires no parameters.A program that demonstrates this is given as follows −Example Live Demoimport java.io.File; public class Demo {    public static void main(String[] args) {       File file = new File("C:" + File.separator + "JavaProgram" + File.separator, "demo1.txt");       System.out.println("File name: " + file.getName());    } }The output of the above program is as follows −OutputFile name: demo1.txtNow let us understand the above program.The name of the specified ... Read More