Let’s say the following is our string with integer and characters −String str = "(29, 12; 29, ) (45, 67; 78, 80)";Now, to extract integers, we will be using the following pattern −\dWe have set it with Pattern class −Matcher matcher = Pattern.compile("\d+").matcher(str);Example Live Demoimport java.util.ArrayList; import java.util.List; import java.util.regex.Matcher; import ... Read More

You can use modify command for this. Let us first us create a table.mysql> create table DemoTable (    StudentId varchar(200) not null,    StudentName varchar(20),    StudentAge int,    StudentAddress varchar(20),    StudentCountryName varchar(20) ); Query OK, 0 rows affected (0.73 sec)Now check the description of table.mysql> desc DemoTable;This ... Read More

The equality of two buffers can be checked using the method equals() in the class java.nio.CharBuffer. Two buffers are equal if they have the same type of elements, the same number of elements and the same sequence of elements. The method equals() returns true if the buffers are equal and ... Read More

Let’s say our file is “input.txt”, which is set read-only −File myFile = new File("input.txt"); myFile.createNewFile(); myFile.setReadOnly();Now, set the above file to writable −myFile.setWritable(true);After that, you can use canWrite() to check whether the file is writable or not.Example Live Demoimport java.io.File; public class Demo {    public static void main(String[] args) ... 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, ... Read More

You can use aggregate function SUM() for this. Let us first create a table −mysql> create table DemoTable    (    Id int NOT NULL AUTO_INCREMENT PRIMARY KEY,    FirstValue int,    SecondValue int,    ThirdValue int    ); Query OK, 0 rows affected (0.57 sec)Insert some records in the ... Read More

An immutable copy of a LocalTime object where some nanoseconds are added to it can be obtained using the plusNanos() method in the LocalTime class in Java. This method requires a single parameter i.e. the number of nanoseconds to be added and it returns the LocalTime object with the added ... Read More

To check capacity in Java, firstly create a list and add elements. After that use ensureCapacity() and increase the capacity.Let us first create an ArrayList and add some elements −ArrayListarrList = new ArrayList(5); arrList.add(100); arrList.add(200); arrList.add(300); arrList.add(400); arrList.add(500);Now, increase the capacity of the ArrayList −arrList.ensureCapacity(15);Meanwhile, with the size() method, you ... Read More

The method java.io.File.list() is used to obtain the list of the files and directories in the specified directory defined by its path name. This list of files is stored in a string array. If the length of this string array is greater than 0, then the specified directory is not ... Read More

A read-only char buffer can be created using the contents of a buffer with the method asReadOnlyBuffer() in the class java.nio.CharBuffer. The new buffer cannot have any modifications as it is a read-only buffer. However, the capacity, positions, limits etc. of the new buffer are the same as the previous ... Read More