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Java Articles
Page 346 of 450
What does the method removeRange(int fromIndex, int toIndex) do in java?
The removeRange() method of the ArrayList class removes all of the elements from this List whose index is between fromIndex and toIndex.Exampleimport java.util.*; public class ArrayListDemo extends ArrayList{ public static void main(String[] args) { ArrayListDemo arrlist = new ArrayListDemo(); arrlist.add(10); arrlist.add(12); arrlist.add(31); System.out.println("The list:" + arrlist); arrlist.removeRange(0,2); System.out.println("The list after using removeRange:" + arrlist); } }OutputThe list:[10, 12, 31] The list after using removeRange:[31]
Read MoreWhat does the method set(int, obj o) do in java?
The set() method of the ArrayList class replaces the element at the specified position in this list with the specified element.Exampleimport java.util.ArrayList; public class Sample { public static void main(String args[]) { ArrayList al = new ArrayList(); System.out.println("Initial size of al: " + al.size()); al.add("C"); al.add("A"); al.add("E"); al.add(1, "A2"); System.out.println("Size of al after additions: " + al.size()); System.out.println("Contents of al: " + al); System.out.println("Size of al after deletions: " + al.size()); ...
Read MoreWhat does the method indexOf(obj o) do in java?
The indexOf(Object) method of the java.util.ArrayList class returns the index of the first occurrence of the specified element in this list, or -1 if this list does not contain the element.Exampleimport java.util.ArrayList; public class ArrayListDemo { public static void main(String[] args) { ArrayList arrlist = new ArrayList(5); arrlist.add("G"); arrlist.add("E"); arrlist.add("F"); arrlist.add("M"); System.out.println("Size of list: " + arrlist.size()); for (String value : arrlist) { System.out.println("Value = " + value); } ...
Read MoreWhat does the method size() do in java?
The size() method of the class java.util.ArrayList returns the number of elements in this list i.e. the size of the list.Exampleimport java.util.ArrayList; public class ArrayListDemo { public static void main(String[] args) { ArrayList arrlist = new ArrayList(5); arrlist.add(15); arrlist.add(20); arrlist.add(25); arrlist.add(22); for (Integer number : arrlist) { System.out.println("Number = " + number); } int retval = arrlist.size(); System.out.println("Size of list = " + retval); } }OutputNumber = 15 Number = 20 Number = 25 Number = 22 Size of list = 4
Read MoreWhat does the method remove(obj o) do in java?
The remove(Object) method of the class java.util.ArrayList removes the first occurrence of the specified element from this list, if it is present. If the list does not contain the element, it is unchanged.Exampleimport java.util.ArrayList; public class ArrayListDemo { public static void main(String[] args) { ArrayList arrlist = new ArrayList(5); arrlist.add("G"); arrlist.add("E"); arrlist.add("F"); arrlist.add("M"); arrlist.add("E"); System.out.println("Size of list: " + arrlist.size()); for (String value : arrlist) { System.out.println("Value = " + ...
Read MoreHow to truncate a file in Java?
The flush() method of the FileWriter class flushes the contents of the file. You can use this method to truncate a file.Exampleimport java.io.File; import java.io.FileWriter; public class FileTruncate { public static void main(String args[]) throws Exception { File file = new File("myData"); FileWriter fw = new FileWriter(file, false); fw.flush(); System.out.println("File truncated"); } }OutputFile truncated
Read MoreHow to capture file not found exception in Java?
While using FileInputStream, FileOutputStream, and RandomAccessFile classes, we need to pass the path of the file to their constructors. In case of a file in the specified path does not exist a FileNotFoundException is raised.Examplepublic class Sample { public static void main(String args[]) throws Exception { File file = new File("myFile"); FileInputStream fis = new FileInputStream(file); System.out.println("Hello"); } }OutputException in thread "main" java.io.FileNotFoundException: myFile (The system cannot find the file specified) ...
Read MoreCan we define a class inside a Java interface?
Yes, you can define a class inside an interface. In general, if the methods of the interface use this class and if we are not using it anywhere else we will declare a class within an interface.Exampleinterface Library { void issueBook(Book b); void retrieveBook(Book b); public class Book { int bookId; String bookName; int issueDate; int returnDate; } } public class Sample implements Library ...
Read MoreWhat is the Eclipse keyboard shortcut for "public static void main(String[] args) " in Java?
To get public static void main(String[] args) line in eclipse without typing the whole line type main and press Ctrl + space then, you will get the option for the main method select it.
Read MoreHow to find package explorer in Java eclipse project?
To view the project explorer, click on Window menu then, click on Show View and select Project Explorer.There is simpler way to open project explorer, when you are in the editor press alt + shift + w and select project explorer.
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