How-to articles, tricks, and solutions about JAVA

The java.lang.UnsupportedOperationException is thrown when an operation is not supported by a class.

The equals() and hashCode() methods are two methods that are defined in the Object class, which is the superclass of all classes in Java.

In Java, the transient keyword is used to indicate that a field should not be serialized when an object is persisted to storage or when an object is transferred over a network.

RecyclerView does not have an onItemClickListener() method because it is not directly responsible for displaying a list of items.

It is generally considered more secure to use a char[] array to store passwords because it can be wiped from memory more easily than a String object.

There are several reasons why an @Autowired field in a Spring bean might be null:

Processing a sorted array can be faster than processing an unsorted array because certain algorithms and operations have a lower average time complexity when the input is already sorted.

Without more context, it is difficult to say why subtracting two times would give a strange result. Here are a few potential explanations:

In Java, the main method is declared as static because the JVM (Java Virtual Machine) needs to be able to invoke it without creating an instance of the class that contains it.

There is no SortedList class in the Java standard library because the List interface already provides a way to store elements in a specific order.

Getters and setters, also known as accessors, are methods that are used to get and set the values of an object's properties.

A java.net.ConnectException: Connection timed out error can occur when a Java application is unable to establish a network connection to the specified host.