How-to articles, tricks, and solutions about JAVA

To check if a file exists in Java, you can use the exists method of the File class from the java.io package. This method returns true if the file exists, and false if it doesn't. Here's an example of how you can use this method:

To concatenate two strings in Java, you can use the + operator.

To connect to a SQL Server database using JDBC, you will need to use the JDBC driver for SQL Server.

To convert a string in the format "2018-04-10T04:00:00.000Z" to a DateTime object in Java, you can use the org.joda.time.DateTime class and the DateTimeFormatter class.

You can use the entrySet() method of the Map interface to get a Set view of the mappings contained in the map, and then create a List from this set using the new

To convert a String to an InputStream in Java, you can use the ByteArrayInputStream class, which allows you to create an InputStream from a byte array.

To convert a String to an int in Java, you can use the parseInt() method of the Integer class. Here's an example:

To convert an int to a long in Java, you can simply use the typecast operator (long) and place it in front of the value you want to convert.

To convert an int to a String in Java, you can use the Integer.toString() method. For example

There are several ways to copy an object in Java. Here are a few options:

Here is one way you could do it in Java:

To create a Java string from the contents of a file, you can use the following code:

There are several ways to declare and initialize an array in Java. Here are a few examples: Declare and initialize an array of integers with size 5

To check if an array contains a particular value in Java, you can use the contains() method of the List interface, which is implemented by the ArrayList class.

To send an HTTP GET request in Java, you can use the java.net.URL and java.net.HttpURLConnection classes.

There are several ways to iterate over the entries in a Map in Java. Here are some options:

To find out your MySQL connection details, you will need to look in your MySQL configuration files. The specific location of these files will depend on how you installed MySQL, but common locations include /etc/my.cnf,

To find out which keystore the Java Virtual Machine (JVM) is using, you can use the javax.net.ssl.KeyManagerFactory class and the getDefaultAlgorithm method.

To find where the JDK is installed on your Windows machine, you can follow these steps:<br>

A NoSuchMethodError is thrown when a program tries to call a method that does not exist in the class or interface.

To generate a random integer within a specific range in Java, you can use the nextInt method of the Random class.

To get a class instance of a generic type T, you can use the new operator and specify the type argument when creating an instance of the class. Here's an example:

To get a java.util.Date object with the time set to 00:00:00 (midnight), you can use the toInstant() method to convert a LocalDate object to an Instant, and then use the atZone() method to convert the Instant to a ZonedDateTime object, and finally use the

To get a platform-dependent new line character in Java, you can use the System.lineSeparator() method.

To get the file extension of a file in Java, you can use the File class and its getName() method to get the file name, and then use the substring() method of the String class to extract the extension from the file name.