Kim Young-han's Practical Java - Intermediate Part 1

This is because many books and lectures published so far have focused on teaching Java's grammar and functions rather than explaining the essential reasons why the technologies provided by Java are necessary.

This course is not just a grammar-focused course, but will also walk you through why this feature is necessary step by step through example code .
And to help you put what you've learned to good use in practice, we'll also teach you the methods most commonly used in practice.

Object class

The Object class is the top-level parent of all classes.

In this lecture, we will learn why the Object class is needed and what functions it provides. We will also learn about the concepts of identity and equality in Java through equals().

Immutable Object

An object that does not change once it is created is called an immutable object.

Many objects provided by Java, including String, wrappers, dates and times, which will be explained later, are provided as immutable objects. Here, we will learn why immutable objects are necessary and how to create immutable objects.

String class

The String class is a class used when handling strings in Java. Here, we will learn about the basic functions of the String object, as well as the differences in functions and performance between StringBuilder and String. We will also take a deep look at how Java optimizes the String class.

Rapper, Class Class

Learn about the limitations of Java primitives and learn wrapper classes to overcome those limitations. You will also learn about auto-boxing and key methods of wrapper classes.

Additionally, we will learn about the Class class that shows information about the class, the System class that provides information about the system, and frequently used classes such as Math and Random.

Enumeration - ENUM

Enumerations are a great feature that provide high type safety.

Here, we will not simply learn the grammar of enumerations, but will talk about why enumerations are essential. And we will also implement a type-safe enumeration pattern that we implemented ourselves in the days when there were no enumerations. We will also learn how to effectively utilize enumerations in practice through various example codes.

Date and time

Calculating dates and times may seem simple on the surface, but it is actually quite difficult. That is why we need to use the libraries provided by Java.

Starting with the history of the Java date and time library, we will explain which date and time classes to use in which situations through various examples.

Nested classes, inner classes

Placing a class inside a class is called a nested class or inner class. The goal here is to master all nested classes.

Explains all nested classes, including static nested classes, inner classes, local classes, and anonymous classes. Rather than simply explaining the grammar, it explains how to use it with code and examples. It also explains the difficult concept of capturing local variables in an easy-to-understand manner with illustrations.

Exception handling

In Java, exception handling syntax is simple, but it is difficult to properly understand why exception handling is necessary and how to utilize it in practice.

Here, we first go back to the days when there was no exception handling. Then, as we gradually improve the example code, we find out one by one why exception handling is essentially necessary.

Finally, we will also provide practical best practices on how to handle exceptions in practice.