For this, use $ifNull operatorLet us first create a collection with documents −> dbquerySelectDemoinsertOne({"Value1":10, "Value2":null}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cefc0ceef71edecf6a1f6b6") } > dbquerySelectDemoinsertOne({"Value1":null, "Value2":30}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cefc0d7ef71edecf6a1f6b7") } > dbquerySelectDemoinsertOne({"Value1":60, "Value2":40}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cefc0e2ef71edecf6a1f6b8") ... Read More

To check whether a node is a root node or not, use the isRoot() method. This returns a boolean value. TRUE if the node is a root node, else FALSE is returned. For example, TRUE is returned since the following node is a root node −node.isRoot()Another example, FALSE is returned ... Read More

At first, create a JDesktoPane −JDesktopPane desktopPane = new JDesktopPane();Now, create an Internal frame and add it to the JDesktopPane −JInternalFrame intFrame = new JInternalFrame("Our Frame", true, true, true, true); desktopPane.add(intFrame); The following is an example to add Internal Frame to a JDesktopPane − package my; import java.awt.BorderLayout; import javax.swing.JButton; ... Read More

The name attribute of the element is used to set the name for a button. More than one button can have the same name, but we can submit different values from these buttons using the name attribute.Following is the syntax −Above, btn_name is the name of the button. Let ... Read More

Use aggregation for this and add the values to an array using the $group and $addToSet operatorLet us first create a collection with documents −> dbspecifyReturnFormatDemoinsertOne({"Subject":"MongoDB"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cefd364ef71edecf6a1f6c0") } > dbspecifyReturnFormatDemoinsertOne({"Subject":"MySQL"}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cefd369ef71edecf6a1f6c1") } > dbspecifyReturnFormatDemoinsertOne({"Subject":"SQL ... Read More

Use the getSiblingCount() method to get the number of siblings of a node in JTree. For example, let’s say we have a node, which isn’t a root node. For that, we will find the sibling count −node1.getSiblingCount()The following is an example to get the number of siblings of a node ... Read More

We will use printjson() for this. Let us first create a collection with documents −> dbprintResultScriptDemoinsertOne({"StudentName":"John", "StudentAge":21}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cf22c02b64a577be5a2bc0b") } > dbprintResultScriptDemoinsertOne({"StudentName":"Carol", "StudentAge":20}); {    "acknowledged" : true,    "insertedId" : ObjectId("5cf22c09b64a577be5a2bc0c") } > dbprintResultScriptDemoinsertOne({"StudentName":"David", "StudentAge":19}); {    "acknowledged" : true,    "insertedId" ... Read More

To set TabLayout Policy to JTabbedPane in Java when all the tabs does not fit in a single run, use the method setTabLayoutPolicy() −JTabbedPane tabbedPane = new JTabbedPane(); tabbedPane.setTabLayoutPolicy(JTabbedPane.SCROLL_TAB_LAYOUT);Above we have set the constant to be SCROLL_TAB_LAYOUT, which is a tab layout policy for providing a subset of available tabs ... Read More

To set the JSlider to be vertical, use the VERTICAL constant while creating the slider −JSlider slider = new JSlider(JSlider.VERTICAL, 0, 100, 60);Now, for the inverted slider i.e. moving from top-to-bottom −slider.setInverted(true);The following is an example to set the slider vertical and move top-to-bottom −Examplepackage my; import javax.swing.JFrame; import javax.swing.JPanel; ... Read More

The HTML DOM Anchor hreflang property is used to set or return the value of the hreflang attribute of a link.Following is the syntax to set the hreflang property −anchorObj.hreflang = language_codeAbove, language_code represents the language of the linked document. This language code examples, include en for English, bn for ... Read More