Java for Complete Beginners (Video), Part 42: Equals and Comparing Strings
This is a tutorial on the vital .equals() method in Java, used for comparing the meaning of objects to find out whether they are equal or not. .equals() is vital in comparing Strings and Doubles; beginners often mistakenly use == … Continue reading
Java for Complete Beginners (Video), Part 41: Writing Text Files
A tutorial on writing text files, Java 7 style. If you want Java 6 style, you can easily take the code here and re-arrange it along the lines of the previous tutorial on reading text files in Java. Writing text … Continue reading
Java for Complete Beginners (Video), Part 40: Try With Resources
Java 7 introduces a great new language feature, “try with resources”. In this tutorial we’ll see how we can use a try block to simply our file reading code quite a lot, ensuring that file handles are closed without the … Continue reading
Java for Complete Beginners (Video), Part 39: Reading Files with FileReader
The most flexible way to read files in Java involves using a sort of Russian doll system of objects; in this tutorial we’ll look at reading text files using such a method. Unfortunately prior to Java 7 we end up … Continue reading
Debugging in Eclipse: Java for Complete Beginners
A video on how to use the debugger in Eclipse. Debugging is something that a lot of developers happily get by without, but it’s something that’s sometimes very useful, and it’s certainly something that every aspiring developer should learn. Debuggers … Continue reading
Java for Complete Beginners (Video), Part 38: Abstract Classes
Abstract classes allow you to define the parent class of a new hierarchy without having to worry about the user actually instantiating the parent. For instance you could create an “Animal” class just to act as the basis for “Dog”, … Continue reading
Java for Complete Beginners (Video), Part 37: Runtime Exceptions
Runtime exceptions are a kind of exception that you’re not forced to handle. They usually point to serious problems with your code, indicating that you need to revise it. The infamous null pointer exception and array out-of-bounds exception are good … Continue reading
Java for Complete Beginners (Video), Part 36: Multiple Exceptions
In this tutorial we’ll take a look at throwing and handling multiple exceptions, plus a look at a popular exam/interview question. Java 7 introduced a new way of handling multiple exceptions; but even if you’re still on Java 6, there … Continue reading
Java for Complete Beginners (Video), Part 35: Throwing Exceptions
In this tutorial we’ll take a look at how to throw your own exceptions in Java. Throwing an exception is a useful thing to do when your method encounters an unexpected error; the exception will immediately return from your method, … Continue reading
Java for Complete Beginners (Video), Part 34: Handling Exceptions
Exceptions are a major part of the Java language; so much so that you can’t write very much code without at least having to handle some of them. In this tutorial we’ll get started with Exceptions, and I’ll also give … Continue reading
Java for Complete Beginners (Video), Part 33: Reading Files
You can use the Scanner class to simplify reading text files quite a bit. In this tutorial we’ll see how to do it, and I’ll also explain how to locate your file on the disk and we’ll look at a … Continue reading
Java for Complete Beginners (Video), Part 32: Anonymous Classes
Anonymous classes in Java are a handy way of creating “one off” objects using un-named classes that you create on the fly. We’ll take a look at how to create them in this tutorial. When the video is running, click … Continue reading
Java for Complete Beginners (Video), Part 31: Generics and Wildcards
A tutorial on using wildcards with generic classes in Java. Want to impress even hardened Java developers with the depth of your Java knowledge? This should do the trick. Wildcards are mostly useful when you want to pass parametrized classes … Continue reading
Java for Complete Beginners (Video), Part 30: Using Generics
This tutorial is on generics; a system for creating “parametrized” classes that allow classes to work with other objects, the type of which you can specify when you instantiate (create objects from) the class. Confused? Hopefully this gentle introduction will … Continue reading
Java for Complete Beginners (Video), Part 29: Upcasting and Downcasting
Understand the import topic of upcasting and downcasting in Java with this tutorial; in this video I’ll explain both concepts, why downcasting requires a special syntax while upcasting doesn’t, and we’ll look at precisely what determines what methods can be … Continue reading
Java for Complete Beginners (Video), Part 28: Casting Numerical Values
A tutorial on casting numerical types; when and why you need casts, and a pitfall to watch out for. When the video is running, click the maximize button in the lower-right-hand corner to make it full screen. Code for this … Continue reading
Java for Complete Beginners (Video), Part 27: Encapsulation and the API Docs
What is encapsulation and what’s the point of it? We’ll take a look at the meaning and benefits of encapsulation in this tutorial. We’ll also see an example of encapsulation in the real world by looking at the API document … Continue reading
Java for Complete Beginners (Video), Part 26: Polymorphism
This is a tutorial on polymorphism; a big word for a fairly simple but very useful concept, without which object-oriented programming would be a lot trickier. When the video is running, click the maximize button in the lower-right-hand corner to … Continue reading
Java for Complete Beginners (Video), Part 25: Public, Private, Protected
Discover the meaning of public, private and protected in the Java programming language. Public, private and protected are confusing for beginners, but once you understand how to use classes, they’re actually quite simple. When the video is running, click the … Continue reading
Java for Complete Beginners (Video), Part 24: Packages
How to use packages in Java. Packages are an important tool for organising your code; you’ll also need to understand packages to use other people’s code. When the video is running, click the maximize button in the lower-right-hand corner to … Continue reading
Java for Complete Beginners (Video), Part 23: Interfaces
A tutorial on interfaces in Java. Discover how you can use interfaces almost everywhere where you’d normally use classes, with one important exception. Interfaces have a variety of uses, including helping to specify functionality, helping to separate one class from … Continue reading
Java for Complete Beginners (Video), Part 22: Inheritance
A tutorial on the important topic of inheritance in Java — one of the fundamental building blocks of OOP (Object Oriented Programming). (Apologies for the dodgy sound on this video). When the video is running, click the maximize button in … Continue reading
Java for Complete Beginners (Video), Part 21: toString()
How to use the important toString() method in Java, and a bit about the Object class that’s the grandfather of all objects in Java. When the video is running, click the maximize button in the lower-right-hand corner to make it … Continue reading
Java for Complete Beginners (Video), Part 20: StringBuilder and String Formatting
How to use StringBuilder, StringBuffer and why you should use them. This video also unveils the mystery of formatting strings with printf() and related methods; vital skills for any Java course or aspiring software developer. When the video is running, … Continue reading
Java for Complete Beginners (Video), Part 19: Static (and Final)
A tutorial on the static keyword in Java. The first part of the tutorial covers the basic meaning of static; after that we look at what you can do with static, including counting objects, assigning IDs to objects automatically, and … Continue reading
Java for Complete Beginners (Video), Part 18: Constructors
A tutorial on constructors in Java; what are they, how to create them, using multiple constructors with different parameters and calling constructors from within other constructors. When the video is running, click the maximize button in the lower-right-hand corner to … Continue reading
Java for Complete Beginners (Video), Part 17: Setters and ‘this’
How to use setters, also known as set methods or mutators, in Java. In this video I also take a look at the ‘this’ keyword and when to use it. When the video is running, click the maximize button in … Continue reading
Java for Complete Beginners (Video), Part 16: Method Parameters
How to pass parameters (values and variables) to your methods; a vital programming skill. I also discuss something that usually confuses beginners — namely, how data flows from one variable to another when you pass the variable to a method. … Continue reading
Java for Complete Beginners (Video), Part 15: Getters and Return Values
Using get methods or “getters” in your Java classes, and how to return values from methods in general. When the video is running, click the maximize button in the lower-right-hand corner to make it full screen. Code for this tutorial: … Continue reading
Java for Complete Beginners (Video), Part 14: Methods
How to add methods (subroutines) to your classes in Java. In this tutorial we’ll look at adding subroutines to our basic Person class, so that the Person objects can do stuff as well as containing data. When the video is … Continue reading
Java for Complete Beginners (Video), Part 13: Classes and Objects
A basic tutorial on classes and objects in Java. What is a class? How do you create objects and classes and how do you use them? When the video is running, click the maximize button in the lower-right-hand corner to … Continue reading
Java for Complete Beginners (Video), Part 12: Multi-dimensional Arrays
How to work with multi-dimensional arrays in Java and info on how multi-dimensional arrays actually work, plus some tips on how to remember which index is which. When the video is running, click the maximize button in the lower-right-hand corner … Continue reading
Java for Complete Beginners (Video), Part 11: Arrays of Strings
A tutorial on String arrays in Java, plus another way to iterate through an array, and more stuff on references vs. values. When the video is running, click the maximize button in the lower-right-hand corner to make it full screen. … Continue reading
Java for Complete Beginners (Video), Part 10: Arrays
How to use arrays of integers in Java; also some stuff on the important difference between values and references. When the video is running, click the maximize button in the lower-right-hand corner to make it full screen. Code for this … Continue reading
Java for Complete Beginners (Video), Part 9: Switch
How to use the switch statement in Java; a construct that many programmers neglect but that invariably appears early on in tests and courses! When the video is running, click the maximize button in the lower-right-hand corner to make it … Continue reading
Java for Complete Beginners (Video), Part 8: Do … While
Do…while loops in Java, plus a look at variable scoping and multi-line comments. In this tutorial I tackle a task that’s often assigned to beginners on Java courses; looping until the user enters some particular input. When the video is … Continue reading
Java for Complete Beginners (Video), Part 7: Getting User Input
How to get console user input in your Java programs using the JDK Scanner class. When the video is running, click the maximize button in the lower-right-hand corner to make it full screen. Code for this tutorial: import java.util.Scanner; public … Continue reading
Java for Complete Beginners (Video), Part 6: If
A tutorial on the if() statement, plus some stuff on using break to break out of loops. When the video is running, click the maximize button in the lower-right-hand corner to make it full screen. Code for this tutorial: public … Continue reading
Java for Complete Beginners (Video), Part 5: For Loops
In the fifth part of the Java tutorial for beginners video series using Eclipse, we look using ‘for’ loops and printf(). Code for this tutorial: public class Application { public static void main(String[] args) { for(int i=0; i < 5; … Continue reading
Java for Complete Beginners (Video), Part 4: While Loops
In the fourth part of the Java tutorial for beginners video series using Eclipse, we look using loops to make your code repeat statements multiple times. We also take a look at conditions. Code for this tutorial: public class Application … Continue reading
Java for Complete Beginners (Video), Part 3: Strings
In the third part of the Java tutorial for beginners video series, we look at working with text using the String class. We also get our first real peek at using classes and objects. Code for this tutorial: public class … Continue reading
Java for Complete Beginners (Video), Part 2: Using Variables
In this second part of the Java tutorial for beginners series, we look at declaring and initializing variables — one of the most basic building blocks of any computer program. Code for this tutorial: public class Application { public static … Continue reading
Java for Complete Beginners (Video), Part 1: A Hello World Program
The first in a series of video tutorials on Java for absolute beginners, using the free Eclipse IDE. In this first video, I show you how to create a “hello world” Java program with a minimum of typing! Before you … Continue reading