How-to articles, tricks, and solutions about JAVA

To get the separate digits of an integer number, you can convert the number to a string, and then use the list() function to convert the string to a list of characters.

If you are trying to execute a query using Hibernate and are getting an error saying "could not extract ResultSet," it could be due to a few different issues:

There are several ways you can pass an object from one activity to another on Android:

In a class, the static keyword is used to declare a static member, which belongs to the class itself rather than an instance of the class. This means that you can access a static member without creating an instance of the class.

To upload a file and JSON data in Postman, you can follow these steps:

To initialize a byte array in Java, you can use the array initializer syntax, like this:

The java.net.BindException: Address already in use: JVM_Bind error occurs when you try to bind a socket to a local address and port, but the address and port are already in use by another process. This can happen when you try to start a server on a port

In Java, constants are usually implemented using the final keyword. The final keyword can be used to declare a variable, a method, or a class as final. A final variable is a variable that cannot be modified after it is initialized, a final method is a met

To make an HTTP POST request using JSON in Java, you can use the HttpURLConnection class available in the java.net package. Here's an example of how to do it:

The trustAnchors parameter must be non-empty error typically occurs when you are trying to create an instance of the SSLContext class in Java and you pass an empty trust store as the trustAnchors parameter.

To make the return type of a method generic in Java, you can use a type parameter. A type parameter is a placeholder for a specific type that will be specified when the method is called.

To remove a single character from a string by its index in Java, you can use the StringBuilder.deleteCharAt() method. Here's an example of how to use it:

The java.lang.NullPointerException error is thrown when an application attempts to use an object reference that has the null value. This usually occurs when you try to call a method or access a field of an object that is null

The StringBuilder and StringBuffer classes in Java are used to create mutable strings. A mutable string is a string that can be modified after it is created, unlike a regular string, which is immutable and cannot be modified.

To sort an array in Java, you can use the Arrays.sort() method of the java.util.Arrays class. This method sorts the elements of the array in ascending order according to their natural ordering.

To use the values of an enum as string literals in Java, you can use the name() method of the Enum class. This method returns the name of the enum value as a string.

To decode base64 data in Java, you can use the Base64.Decoder class introduced in Java 8. Here's an example of how to use it:

This error typically occurs when you are trying to use the log4j library to log messages in your Java application, but the library is not properly configured.

To add a string to a string array in Java, you can use the Arrays.copyOf() method to create a new array that is one element larger than the original array, and then use a loop to copy the elements of the original array into the new array. Here's an exampl

This error typically occurs when you are trying to use the HttpServlet class in a Java project, but the necessary libraries are not included in the project's classpath. To fix this error, you need to add the servlet-api.jar library to your project's class

To determine if a string is an integer in Java, you can use the isDigit() method of the Character class to check if each character in the string is a digit. Here's an example:

You can use the toArray() method of the ArrayList class to convert an ArrayList of strings to a string array. Here's an example:

To iterate over the key-value pairs in a HashMap in Java, you can use the forEach() method and provide a lambda expression as an argument. Here's an example:

To set the JAVA_HOME environment variable on Windows 7, follow these steps:<br>

If you are getting an exception when using Thread.sleep(x) or wait(), it could be because one of these methods has been interrupted.