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To create a JMenuBar component, use the JMenuBar class −JMenuBar menuBar = new JMenuBar();Now, create menus inside the MenuBar −JMenu fileMenu = new JMenu("File");Add the above menu to the MenuBar −menuBar.add(fileMenu);The following is an example to create a JMenuBar Component in Java −Examplepackage my; import java.awt.event.KeyEvent; import javax.swing.JFrame; import javax.swing.JMenu; import javax.swing.JMenuBar; import javax.swing.JMenuItem; public class SwingDemo { public static void main(final String args[]) { JFrame frame = new JFrame("MenuBar Demo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JMenuBar menuBar = new JMenuBar(); JMenu fileMenu = new JMenu("File"); fileMenu.setMnemonic(KeyEvent.VK_F); ... Read More
We will use the Null type here. Following are the null types with the alias −TypeNumberAliasDouble1“double”String2“string”Object3“object”Array4“array”Binary data5“binData”Undefined6“undefined”ObjectId7“objectId”Boolean8“bool”Date9“date”Null10“null”Regular Expression11“regex”Following is the syntax for type 10 i.e. null −db.yourCollectionName.find({"yourFieldName":{ $type: 10 } });The above syntax will find only those documents which have null value. Let us first create a collection with documents −> db.mongoDbEqualDemo.insertOne({"Age":34}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7e9121a844af18acdffa3") } > db.mongoDbEqualDemo.insertOne({"Age":""}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7e9161a844af18acdffa4") } > db.mongoDbEqualDemo.insertOne({"Age":null}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7e9191a844af18acdffa5") } > db.mongoDbEqualDemo.insertOne({"Age":56}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7e91e1a844af18acdffa6") } > db.mongoDbEqualDemo.insertOne({}); ... Read More
The java.lang.Class is one of the most important class in Java and it can provide several utility methods like getClass(), forName() which is used to find and load a class. It can also provide methods like Class.newInstance() which is the backbone of reflection and allow us to create an instance of a class without using new() operator.Importance of java.lang.ClassInstances of the class Class represent classes, interfaces, enum and annotation in a running Java application.Whenever a java file is compiled, the compiler will insert a public, static, final field named Class of the type java.lang.Class into generated .class fileEach and every class exposes its code in the form of an ... Read More
Using Css style we can hide or show HTML elements in javascript. Css provides properties such as block and none to hide/show the HTML elements.Hiding an elementExampleIn the following example when the "Hideme" button has clicked the text in the paragraph tag has been disappeared as shown in the output.Live Demo Using JavaScript to hide HTML elements.
You can convert an object array to an integer array in one of the following ways −By copying each element from integer array to object array −Exampleimport java.util.Arrays; public class ObjectArrayToStringArray { public static void main(String args[]){ Object[] objArray = {21, 58, 69, 33, 65}; int length = objArray.length; int intArray[] = new int[length]; for(int i=0; i
The HTML DOM Input Checkbox disabled property sets/returns whether Input Checkbox is to be enabled or disabled.SyntaxFollowing is the syntax −Returning boolean value − true/falseinputCheckboxObject.disabledSetting disabled to booleanValueinputCheckboxObject.disabled = booleanValueBoolean ValuesHere, “booleanValue” can be the following −booleanValueDetailstrueIt defines that the checkbox is disabled.falseIt defines that the checkbox is not disabled and it is also the default value.ExampleLet us see an example of Input Checkbox disabled property − Live Demo Student Details Biology: Mathematics: Physics: Psychology: Enable Subjects function enableCheckboxes(){ var enableCheckboxes ... Read More
The HTML DOM Input FileUpload accept property returns a string, which is the value of the accept attribute of FileUpload. User can also set it to a new value.SyntaxFollowing is the syntax −Returning string valueinputFileUploadObject.acceptSetting value attribute to a string valueinputFileUploadObject.accept = valueExampleLet us see an example of Input FileUpload accept property − Live Demo Input FileUpload accept form { width:70%; margin: 0 auto; text-align: center; } * { padding: 2px; margin:5px; } input[type="button"]{ ... Read More
Yes, we can sort a list with Lambda. Let us first create a String List:List list = Arrays.asList("LCD", "Laptop", "Mobile", "Device", "LED", "Tablet");Now, sort using Lambda, wherein we will be using compareTo():Collections.sort(list, (String str1, String str2) -> str2.compareTo(str1));The following is an example to sort a list with Lambda in Java:Exampleimport java.util.Arrays; import java.util.Collections; import java.util.List; public class Demo { public static void main(String... args) { List list = Arrays.asList("LCD", "Laptop", "Mobile", "Device", "LED", "Tablet"); System.out.println("List = "+list); Collections.sort(list, (String str1, String str2) -> str2.compareTo(str1)); System.out.println("Sorted List ... Read More
Here we will see, how to terminate the threads in C++11. The C++11 does not have direct method to terminate the threads.The std::future can be used to the thread, and it should exit when value in future is available. If we want to send a signal to the thread, but does not send the actual value, we can pass void type object.To create one promise object, we have to follow this syntax −std::promise exitSignal;Now fetch the associated future object from this created promise object in main function −std::future futureObj = exitSignal.get_future();Now pass the main function while creating the thread, pass ... Read More
This method retrieves the list of System functions supported by the current database. The names returned by this method are the Open CLI System function names.This method returns a String value holding the list of functions separated by commas (", ").To get the list of the System functions supported by the underlying database −Make sure your database is up and running.Register the driver using the registerDriver() method of the DriverManager class. Pass an object of the driver class corresponding to the underlying database.Get the connection object using the getConnection() method of the DriverManager class. Pass the URL the database and, user ... Read More