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Articles by George John
Page 55 of 79
How to make a JTree editable in Java?
To make JTree editable in Java, use the TreeCellEditor class. With that, set the setEditable() method to true −TreeCellEditor editor = new DefaultCellEditor(textField); tree.setEditable(true); tree.setCellEditor(editor);The above will make the tree editable. The following is an example to make a JTree editable in Java −Examplepackage my; import javax.swing.DefaultCellEditor; import javax.swing.JFrame; import javax.swing.JTextField; import javax.swing.JTree; import javax.swing.tree.DefaultMutableTreeNode; import javax.swing.tree.TreeCellEditor; public class SwingDemo { public static void main(String[] args) throws Exception { JFrame frame = new JFrame("Demo"); DefaultMutableTreeNode node = new DefaultMutableTreeNode("Products"); DefaultMutableTreeNode node1 = new DefaultMutableTreeNode("Clothing"); DefaultMutableTreeNode node2 = ...
Read MoreCan we get total number of rows in a MySQL database?
To get the total number of rows in a MySQL database, you can use aggregate function SUM() along with inbuilt column TABLE_ROWS from INFORMATION_SCHEMA.TABLES.The syntax is as follows−SELECT SUM(TABLE_ROWS) FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = database();Let’s say we are using the database with the name ‘sample’.Now we will get the total number of rows in a MySQL database−mysql> SELECT SUM(TABLE_ROWS) FROM INFORMATION_SCHEMA.TABLES WHERE TABLE_SCHEMA = database();This will produce the following output−+-----------------+ | SUM(TABLE_ROWS) | +-----------------+ | 2043 | +-----------------+ 1 row in set (22.11 sec)
Read MoreHow can I set a table in a JPanel in Java?
Let us first set rows and columns for our table −String[][] rec = { { "1", "Steve", "AUS" }, { "2", "Virat", "IND" }, { "3", "Kane", "NZ" }, { "4", "David", "AUS" }, { "5", "Ben", "ENG" }, { "6", "Eion", "ENG" }, }; String[] header = { "Rank", "Player", "Country" };Now, set the above in a table as rows and columns −JTable table = new JTable(rec, header);Add the table in the panel −JPanel panel = new JPanel(); panel.add(new JScrollPane(table));The following is an example to create a table in a panel −Examplepackage my; ...
Read MoreHow to update MySQL column with random value?
To update column with random value, you can use the below syntax−update yourTableName set yourColumnName =round(1+rand()*100);The above syntax will generate a value between 1 to 100. Let us see an example and create a table−mysql> create table DemoTable ( Number int ); Query OK, 0 rows affected (0.46 sec)Insert records in the table using insert command −mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.17 sec) mysql> insert into DemoTable values(100); Query OK, 1 row affected (0.11 sec) mysql> insert into DemoTable values(80); Query OK, 1 row affected (0.20 sec) mysql> insert into DemoTable values(100000); ...
Read MoreDisable Tooltip for a component with an already enabled tooltip in Java
Let’s say we have set the tooltips for all the components using the following method in Java, for example −setToolTipText("Enter Age");Here, we have already enabled tooltips for all the components using the setToolTipText(). But, after enabling all of them, we disabled the tooltips using the following −ToolTipManager.sharedInstance().setEnabled(false);The following is an example to disable Tooltip for a component with an already enabled tooltip −Examplepackage my; import java.awt.GraphicsEnvironment; import java.awt.GridLayout; import java.awt.Point; import javax.swing.JFrame; import javax.swing.JLabel; import javax.swing.JPasswordField; import javax.swing.JTextField; import javax.swing.SwingConstants; import javax.swing.ToolTipManager; public class SwingDemo { public static void main(String[] args) throws Exception { JFrame.setDefaultLookAndFeelDecorated(true); ...
Read MoreHow to create a database on command line in MySQL?
First, you need to open the command prompt. You can open using shortcut windows+R key.The screenshot is as follows −Now type CMD and press OK button −Now the following command prompt would be visible −Now reach the MySQL bin directory. The screenshot is as follows −Following is the query to run MySQL in the command line to create a database −Now you can check the database is created or not using SHOW DATABASES command −mysql> SHOW DATABASES;This will produce the following output −+---------------------------+ | Database | +---------------------------+ | bothinnodbandmyisam ...
Read More8085 program to count number of elements which are less than 0A
In this section we will count elements which are lesser than 0AH using 8085.problem StatementThere is an array of some elements. Write 8085 Assembly language program to count number of elements that are lesser than 0AH.DiscussionThe array is placed at location F051H onwards. The F050 is holding the size of the array. The logic is simple. At first we will take the array size into the B register. The C register will count number of elements less than 0AH. We will take numbers one by one from memory, then compare it with 0A. if the CY flag is set it ...
Read MoreHow to create a horizontal slider with custom min, max, and initial value in Java
While creating horizontal slider, we can set custom values as well. Let us take three integer variable and set the int values for min, max as well as the initial value of the slider −int val = 75; int min = 0; int max = 100;Set it to the slider while creating a new slider. Here, we have set the constant to be HORIZONTAL, since we are creating a horizontal slider −JSlider slider = new JSlider(JSlider.HORIZONTAL, min, max, val);The following is an example to create a horizontal slider with custom min, max and initial value −Examplepackage my; import java.awt.Color; import ...
Read MoreDisplay only the horizontal scrollbar in Java
To display only the horizontal scrollbar, use the VERTICAL_SCROLLBAR_NEVER constant, which eventually displays only the horizontal scrollbar.The following is an example to display only the horizontal scrollbar in Java −Examplepackage my; import java.awt.BorderLayout; import java.awt.Dimension; import javax.swing.Box; import javax.swing.JButton; import javax.swing.JFrame; import javax.swing.JScrollPane; public class SwingDemo { public static void main(String args[]) { JFrame frame = new JFrame("Demo"); frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE); JButton button1 = new JButton("Online Compiler"); JButton button2 = new JButton("Quiz"); JButton button3 = new JButton("Questions and Answers"); JButton button4 = new ...
Read More8085 program to find the element that appears once
In this program we will see how to find a number who appears only once in an array of elements.Problem StatementWrite 8085 Assembly language program to find a number who appears only once in an array of elements. The size of the array is stored at location F100; the numbers are stored from memory location F101 onwards. The result will be stored at F150.DiscussionThe logic behind this problem is simple. Though it may find some wrong results in some cases. It can find the number if there is only one number which is appeared once, and rest of the numbers ...
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