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In Java, an array is a container object that holds a similar type of data (elements), but has a fixed size. You can declare it by assigning values in curly braces or creating it using the new keyword by specifying the size. A List in Java is an interface that represents a sequence of elements of the same type (duplicates are allowed) and has a dynamic size. To create an object of the List interface, you can use one of its classes, such as ArrayList, Stack, Vector, etc.Converting an Array to a List in JavaSometimes we need to insert more data ... Read More
A Triangle is a polygon that has 3 sides, and it consists of three sides and three vertices. The sum of the three internal angles is up to 180 degrees. Below is the diagram of a triangle having three sides (a, b, and c): In a valid triangle, if you add any two sides, then it will be greater than the third side. As per our problem statement, we have to check if a triangle is valid or not, if three sides are given, using the Java programming language. Suppose a, b and c are the three sides of ... Read More
LookupError in Python is the base class for errors that occur when a lookup using a key or index fails to find the expected value. This includes exceptions like IndexError and KeyError. If any lookup operation fails, a LookupError or one of its subclasses is raised. In this article, you will learn how to catch LookupError exceptions in Python and handle them to prevent your program from crashing abruptly. LookupError is commonly raised when - You access an invalid index in a list or a tuple. You use a missing key ... Read More
Java ArithmeticException The ArithmeticException of java.lang package is an unchecked exception in Java. It is raised when an attempt is made to use a wrong mathematical expression in the Java program. An example of ArithmeticExeption is division by 0. If you divide two numbers and the number in the denominator is zero. The Java Virtual Machine will throw ArithmeticException. Example: Throwing ArithmeticException In the following Java program, we try a mathematical operation where we divide a number by 0. public class ArithmeticExceptionTest { public static void main(String[] args) { int a ... Read More
The Java team and developer community suggest us to follow naming conventions. They are just conventions and are not mandatory but help in writing Java programs that are more understandable and easier to read. For example, class names should generally be nouns, and interface names should be adjectives. Additionally, capitalize the first letter of each separate word. The names used for classes, variables, and methods are called identifiers. Need to Follow Java Naming Conventions Following are the reasons to follow naming conventions: Multiple developers work on the same project simultaneously. Names that follow naming standards reduce ... Read More
The NumberFormatException is a class that represents an unchecked exception thrown by parseXXX() methods when they are unable to format (convert) a string into a number. Here, the parseXXX() is a group of Java built-in methods that are used to convert string representations of numbers into their corresponding primitive data types. Causes for NumberFormatException in Java The NumberFormatException extends IllegalArgumentException class of java.lang package. It can be thrown by many methods/constructors of the classes. Following are some of them: int parseInt(String s): It throws NumberFormatException if ... Read More
An interface can be used to define a contract for behavior that classes must implement, and it can also act as a contract between two systems to interact. An abstract class is mainly used to define default behavior for subclasses. All child classes inherited from the abstract class can override or extend its methods. If we compare an interface and an abstract class, both can contain abstract methods and cannot be instantiated directly. Also, both are used to achieve abstraction. We may often get confused about when to use an abstract class and when to use an interface in Java. ... Read More
Complex numbers are expressed in the form of p + iq, where p and q indicate real numbers and i represents imaginary numbers. For instance, 8.2 + 5.6i is a complex number, where 8.2 is the real part and 5.6i is the imaginary part. As you can see, the real number part contains an integer value (mathematical, not Java integer), and the imaginary part has an additional symbol i. In this article, we will understand how to add two complex numbers in Java. Adding Complex Numbers Since complex numbers are divided into two parts (real and imaginary), the real numbers ... Read More
In Java if you try to print a List (or any) object directly using the print statement a hash-code of the object will be printed (default behaviour). If you want to print each element of your object (such as List, Array, etc.) or perform any operation on them one by one, you need to iterate through it. Java provides various ways to iterate through objects. Following are different approaches to iterate through a List object: Using For Loop Using While Loop Using Iterator Object Iterate over ... Read More
A List is a sequence of elements of similar data types, and like an array, its elements are stored at specific indices, which can be accessed and searchable through the index (i.e., starting at index 0). We can search through each element in the list and retrieve its index (or position) if it is found in the list. We can search in a List in the following ways - Using indexOf() Method of List Interface Using lastIndexOf() Method Using Comparison Approach Searching in a List using ... Read More