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Articles on Trending Technologies
Technical articles with clear explanations and examples
How to change JTable's header font in Java
To change the table header font, you need to first get the header -JTableHeader tableHeader = table.getTableHeader();Now, use the Font class to set the new font. Here, we have set the font face to be Verdana, style as PLAIN and font size as 14 -Font headerFont = new Font("Verdana", Font.PLAIN, 14);Now, set this font to table header -tableHeader.setFont(headerFont);The following is an example to change the header font -Examplepackage my; import java.awt.Color; import java.awt.Font; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.table.JTableHeader; public class SwingDemo { public static void main(String[] argv) throws Exception { Integer[][] marks = ...
Read MoreFind a strict document that contains only a specific field with a fixed length?\\n
You can use $where operator for this. Let us first create a collection with documents −>db.veryStrictDocumentDemo.insertOne({"StudentFirstName":"John", "StudentLastName":"Doe", "StudentAge":23}); { "acknowledged" : true, "insertedId" : ObjectId("5cda4bcdb50a6c6dd317adb8") } > db.veryStrictDocumentDemo.insertOne({"StudentFirstName":"Larry"}); { "acknowledged" : true, "insertedId" : ObjectId("5cda4bdbb50a6c6dd317adb9") } >db.veryStrictDocumentDemo.insertOne({"StudentFirstName":"David", "StudentLastName":"Miller"}); { "acknowledged" : true, "insertedId" : ObjectId("5cda4becb50a6c6dd317adba") } > db.veryStrictDocumentDemo.insertOne({"StudentFirstName":"Chris"}); { "acknowledged" : true, "insertedId" : ObjectId("5cda4bfbb50a6c6dd317adbb") } > db.veryStrictDocumentDemo.insertOne({"StudentFirstName":"Bob", "StudentLastName":"Brown"}); { "acknowledged" : true, "insertedId" : ObjectId("5cda4c6db50a6c6dd317adbc") }Following is the query to display all documents from a collection with the help of find() method −> db.veryStrictDocumentDemo.find();This will produce the following output ...
Read MoreProgram to calculate area and volume of a Tetrahedron
A tetrahedron is a pyramid with triangular base i.e. it has a base that is a triangle and each side has a triangle. All the three triangles converge to a point. As in the figure, Code Logic − The code to find the area and volume of tetrahedron uses the math library to find the square and square-root of a number using sqrt and pow methods. For calculating the area we take a floating point and the value of the expression “((sqrt(3)*a*a))” is given to it. Another variable get the value of volume of the tetrahedron that is evaluated by ...
Read MoreWhy strict aliasing is required in C?
Here we will see, why we should use the strict aliasing in C. Before discussing that part, let us see one code, and try to analyze the output.Example#include int temp = 5; int* var = &temp; int my_function(double* var) { temp = 1; *var = 5.10; //this will change the value of temp return (temp); } main() { printf("%d", my_function((double*)&temp)); }Output1717986918If we call the function my_function, then it will return 1. We can also call this using my_function((double*)&temp). This is supposed to return 1, but here we can see that this is returning something else. This code was made to return constant 1 only. To fix this problem, we can use Strict ...
Read MoreHow do you update a MongoDB document while replacing the entire document?
Let us first create a collection with a document −>db.replacingEntireDocumentDemo.insertOne({"StudentFirstName":"John", "StudentLastName":"Smith", "StudentCountryName":"US"}); { "acknowledged" : true, "insertedId" : ObjectId("5cd3119bb64f4b851c3a13e8") }Following is the query to display document from a collection with the help of find() method −> db.replacingEntireDocumentDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cd3119bb64f4b851c3a13e8"), "StudentFirstName" : "John", "StudentLastName" : "Smith", "StudentCountryName" : "US" }Following is the query to update a MongoDB document while replacing the entire document −>db.replacingEntireDocumentDemo.update({"StudentFirstName":"John", "StudentLastName":"Smith", "StudentCountryName":"US"}, {"StudentFirstName":"David", "StudentLastName":"Miller", "StudentCountryName":"AUS"}); WriteResult({ "nMatched" : 1, "nUpserted" : 0, "nModified" : 1 })Let us display all the records from the collection ...
Read MoreCan we hide the table header from a JTable in Java?
Yes, we can hide the header from a table. Use the setTableHeader() method and set it to null -table.setTableHeader(null);Above, the table is our JTable -JTable table = new JTable(marks, col)The following is an example to hide the table header -Examplepackage my; import java.awt.Color; import java.awt.Font; import javax.swing.JFrame; import javax.swing.JScrollPane; import javax.swing.JTable; import javax.swing.table.JTableHeader; public class SwingDemo { public static void main(String[] argv) throws Exception { Integer[][] marks = { { 70, 66, 76, 89, 67, 98 }, { 67, 89, 64, 78, 59, 78 }, ...
Read MoreHow do I remove a string from an array in a MongoDB document?
You can use $pull operator to remove a string from an array. Let us first create a collection with documents −> db.removeAStringDemo.insertOne({"Score":[45, 67, 89, "John", 98, 99, 67]}); { "acknowledged" : true, "insertedId" : ObjectId("5cda5224b50a6c6dd317adbd") }Following is the query to display all documents from a collection with the help of find() method −> db.removeAStringDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cda5224b50a6c6dd317adbd"), "Score" : [ 45, 67, 89, "John", 98, 99, 67 ] ...
Read MoreProgram for Christmas Tree in C
Here we will see one interesting problem. In this problem, we will see how to print Christmas tree randomly. So the tree will be flickering like Christmas tree lights.To print a Christmas tree, we will print pyramids of various sizes just one beneath another. For the decorative leaves a random character is printed from a given list of characters. The height and randomness is adjustable.Here after generating a tree, the whole screen is cleared, then generate again, that’s why this is looking like flickering tree.Example#include #include #include #include #define REFRESH_RATE 40000 #define RANDOM_NESS 5 // The ...
Read MoreHow to make an icon in the action bar with the number of notifications in Android?
This example demonstrate about How to make an icon in the action bar with the number of notifications in AndroidStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. ...
Read MorePush new key element into subdocument of MongoDB?
You can use $set operator for this. Following is the syntax −db.yourCollectionName.update({"_id" : yourObjectId }, {$set: { "yourOuterFieldName.anyInnerFieldName": yourValue}});Let us first create a collection with documents −> db.pushNewKeyDemo.insertOne({"UserId":100, "UserDetails":{}}); { "acknowledged" : true, "insertedId" : ObjectId("5cda58f5b50a6c6dd317adbf") }Following is the query to display all documents from a collection with the help of find() method −> db.pushNewKeyDemo.find();This will produce the following output −{ "_id" : ObjectId("5cda58f5b50a6c6dd317adbf"), "UserId" : 100, "UserDetails" : { } }Following is the query to push new key element into subdocument of MongoDB −> db.pushNewKeyDemo.update({"_id" : ObjectId("5cda58f5b50a6c6dd317adbf")}, {$set: { "UserDetails.UserName": "David Miller"}}); WriteResult({ "nMatched" : 1, ...
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