These java basic tutorials in intended for absolute beginners. If you are just beginning to learn java, you should go through these tutorials, otherwise skip them.
Convert decimal to hexadecimal by hand with worked examples, and in Java with Integer.toHexString(), String.format() and HexFormat. Also covers hex to decimal, negative numbers and invalid input.
A Java tutorial for beginners on Java 25, the current LTS release. Install JDK 25, write a first program as a compact source file and as a classic class, add a JUnit 6 test, and follow a 12-step learning path to the best howtodoinjava tutorials for each topic.
As a best practice in Java, POJO classes or Data objects always declare the fields private and expose their access through the getter methods. On rare occasions, we may encounter situations when the member fields are private, and the class does not provide the public accessor methods. For example, the …
Beginning Java 18, we can use Math.divideExact() method that throws an ArithmeticException if the result overflows. Learn with example.
This Java tutorial explores what are absolute values, the overflow, and underflow problems of Math.abs() method, and how Java 15 Math.absExact() solves them.
To convert decimal to hexadecimal, divide by 16 repeatedly and read the remainders in reverse, so 269 becomes 10D. See a worked division table, a table of common conversion examples, and the Java one-liners for both directions.
Learn the differences between Sourcepath, Classpath and Buildpath and how they contribute to an application’s development, build and deployment phases.
Learn to implement the builder pattern style fluent API and copy constructors in Java records for creating immutable records with examples.
Java has 51 reserved words and 16 contextual keywords that cannot be used as identifiers in the code. Programmers should not use these keywords for other purposes.
Learn to convert a given Java object into a Map using different solutions including Jackson ObjectMapper, Gson and Java reflection.
Learn to round off a given floating point number to 2 decimal points in Java. As the best practice, always use the Decimal class with rounding mode set to HALF_EVEN.
Learn to print formatted output in Java using the format() and printf() methods. Learn to format strings, date-time, floats with precision.
Java ternary operator is a conditional operator and can be used as a replacement for a simple if-else statement or a switch statement.
After the legacy Java finalization has been deprecated (JEP-421) in Java 18, learn the basics of Cleaner API and how to use it.
Java is one of the most popular programming languages for developing all kinds of desktop applications, web applications and mobile apps. The following articles will help you quickly become familiar with Java language and move towards more complex concepts such as API and cloud development. 1. Java Language Basics Start …
Learn to install Java on 64-bit Windows machines in this step-by-step guide. 1. Navigate to the Oracle Java Download Page Navigate to the Java download page for the latest Java release. Click on the link “JDK Download”. 2. Download the zip or Exe Package Here you have two choices: 2.1. …
Learn to write your first “Hello World” program in Java. It is often used to verify that the Java runtime is setup correctly.
Learn about traditional instanceof operator, enhancements introduced with pattern matching and the scope of pattern variables with examples.
The program arguments passed at launching the Java program are called command line arguments. While launching the program we can pass additional arguments (no limit of numbers of arguments).
Java naming conventions are sort of guidelines that application programmers are expected to follow to produce consistent and readable code throughout the application. If teams do not follow these conventions, they may collectively write an application code that is hard to read and difficult to understand. Always try to give …
Java hashCode() and equals() methods. Learn contract between hashCode and equals methods. How to correctly override both methods and best practices.
Learn about Java wrapper classes, their usage, conversion between primitives and objects; and autoboxing and unboxing with examples. 1. Java Wrapper Classes In Java, we have 8 primitive data types. Java provides type wrappers, which are classes that encapsulate a primitive type within an Object. A wrapper class wraps (encloses) …
Inside a Java program, we can write a special text that will be ignored by the Java compiler — known as the comment. Comments allow us to exclude code from the compilation process (disable it) or clarify a piece of code to yourself or other developers. Learn everything about Java comments, …
In traditional programming languages, such as Java, a variable is a placeholder for storing a value of a particular type: a string, a number, or something else. This Java tutorial discusses what a variable is and the types of variables. Also, look at the example of how to declare a variable in Java. We …
JDK, JRE and JVM is very common words when developers talk about java applications and their development environments. Let’s find out the differeneces between these words.
Use given syntax examples for setting CLASSPATH for any java application runtime, in windows and linux environments.
Java maintains a Set of system properties that can be accessed in the runtime by executing programs. Each system property is a key-value pair. For example, one such system property is “java.version”=”1.7.0_09“. We can retrieve all the system properties via System.getProperties() or we can also retrieve individual property via System.getProperty(key) …
The static import statements import the static fields and methods from a class and allow them to be used without the class reference.
Classes are the basic units of programming in the object-oriented paradigm. In this tutorial, learn to write Java class and how to create object in Java.
A block statement is a sequence of zero or more statements enclosed in braces. A block statement is generally used to group together several statements, so they can be used in a situation that requires you to use a single statement. 1. What is a Block Statement? Generally, a java …
Every type of statement in Java with a short example: declaration, expression, control flow, jump, block, empty, try, synchronized, labeled and assert statements, plus switch expressions, yield and pattern matching in switch.
Learn about available Java operators, and precedence order and understand their usages with examples. We will also try to understand when to use which operator and what to expect in the result. 1. Java Operators An operator is a symbol that performs a specific operation on one, two, or three …
We must have heard the terms Little-Endian and Big-Endian many times in your engineering course. Let’s quickly recap the concept behind these words. 1. Little-Endian vs Big-Endian These two terms are related to the direction of bytes in a word within CPU architecture. Computer memory is referenced by addresses that …
Learn about various data types in Java. Learn the differences between primitive datatypes and non-primitive datatypes (or reference datatypes). We will also learn about the data types sizes and best practices for using datatypes in Java. 1. How to Declare a Variable in Java? In Java, typically datatypes are associated …
Java is concurrent, object-oriented, and intended to let application developers “write once, run anywhere” (WORA). Java is considered a fast language, almost as fast as languages like C and Rust, but it uses a lot of memory in comparison to these languages. 1. What is Java Programming Language Java is …
Java has eight primitive data types that hold plain values, not object references. Sizes, ranges, defaults, literals, overflow, floating-point precision, casting rules and wrapper classes, with tested Java 25 examples.
In computer architecture, 64-bit computing is the use of processors that have datapath widths, integer size, and memory addresses widths of 64 bits (eight octets/bytes). Also, 64-bit CPU and ALU architectures are those that are based on registers, address buses, or data buses of that size. From the software perspective, …
The “java.exe” and “javaw.exe” are Java executables on the Windows platform used to launch the GUI and Text-based Java programs.
Java compiler rearranges the statements we write in a Java program for performance improvements. Learn to generate the byte code for a class file to see how they have been rearranged.
Java is passed by value and not pass-by-reference. If it had been pass-by-reference, we should have been able to C like swapping of objects.
Have you ever tried to reason why Java’s main() method is public, static and void? Why its name is main? What happens inside JVM when you invoke main() method? What is the purpose of main method? Let’s find out. Since Java 21, we can create instance main() methods that do …
Learn Java finalize() signature, the purpose of finalization, how can we call finalize() method manually, and why you should not use it.
Learn about immutable objects, records and collections in Java and create a Java class immutable step by step with examples.
HowToDoInJava provides tutorials and how-to guides on Java and related technologies.
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