Why Java?

Java compared to other programming languages

Java is a member of the class of object-oriented programming languages, where objects and types offer a convenient abstraction to think about the code that you write. The use of types avoids common mistakes in other languages. Java is also considered a strongly typed language, meaning that it applies strict typing rules at compile time. Other popular programming languages such as Javascript, Python, R or Matlab are not as strongly typed as is Java and do not require users to be aware of the typing rules. If you start learning one of those languages, you would need to learn the typing rules before you can use Java. When moving from Java to one of those languages, you have learned a good structured way to avoid confusion of data types in a language that is more flexible. It is thus easier to move from Java to one of these than the other way around. There are, however, more languages that use objects and types, such as C++ and C. Still, Java is easier to learn because it does not involve difficult memory management. Learning Java will thus provide you with a good basis for learning many other popular (object-oriented and procedural) programming languages.

Another important reason for the popularity of Java is that a Java program can be run on any platform. This means that you can easily share your written program with someone else and that this person can directly run your code without having to make changes or to transform the code to a different format. That is made possible by the Java Compiler, which translates the source code written by programmers to so-called bytecode. This bytecode is then executed by a program called the Java Virtual Machine (JVM), that is available for many hardware platforms. The JVM technology is very powerful and clever, and can decide to convert the bytecode to CPU-specific Assembly to make the code run very efficiently.

Introduction to Programming

Earlier, you have taken the course Introduction to Programming. You may want to visit the website of Introduction to Programming to recall things that you have learned last year. Here, you are provided with a very short recap only.

The first program that you have written has probably looked something like this:

public class HelloWorld {
    public static void main(String[] args) {
        System.out.println("Hello world!");
    }
}

In the weeks after, you have learned to use loops to prevent repetitive code and if-statements to account for multiple cases. To store large quantities of values, you have learned to use arrays and lists. Also, you have written methods to structure your code and used objects to create different instances of one construct.

This course

In this course, you will become more experienced with some of the most important concepts related to Object Oriented Programming in Java. In essence, our aim is that you will be able to write Java programs to solve complex problems that you will encounter during your studies, and learn valuable concepts that allow you to easily learn more complex features of languages such as Python and R.

for (int i = 0; i < 10; i++); {
    System.out.println(i);
}

public static String repeat(String text, int repetitions) {
    int i = 0;
    StringBuilder sb = new StringBuilder();
    while (i < repetitions) {
        sb.append(text);
        i++;
    }
    return sb.toString();
}

public static int sumProduct(int[] listA, int[] listB) {
    int result = 0;
    for (int i=0; i < listA.length && i < listB.length; i++) {
        result += listA[i] * listB[i];
    }
    return result;
}

public List<String> makeList() {
    List<String> result = new ArrayList<>();
    while (moreComing()) {
        result.add(nextString())
    }
    return result;
}