Story of passing Java Silver SE8 (Oracle Certified Java Programmer, Silver SE 8)

Introduction

I am an engineer who has been in the company for the third year since April. My knowledge of Java is as much as creating a Java web application with Servlet in business. I'm almost a beginner. I feel that I was able to deepen my knowledge of object-oriented languages or Java-specific language specifications through studying this exam. I think this qualification is recommended for those who are told by the company to get some vendor qualifications like myself, or who are wondering what to take to improve their skills as an engineer.

What is Oracle Certified Java Programmer, Silver SE 8?

This is an excerpt from the official.

It is a qualification for development beginners who has the basic programming knowledge required for Java application development and can perform development work under the guidance of advanced users. The purpose is to evaluate not only everyday programming skills, but also the ability to respond to situations that occur in various projects.

Learning time

From one month before the test, it took 30 minutes a day on weekdays and 2 to 3 hours on holidays.

Learning method

[Thorough capture Java SE 8 Silver problem collection [1Z0-808] correspondence](https://www.amazon.co.jp/%E5%BE%B9%E5%BA%95%E6%94%BB%E7% 95% A5-Java-Silver-% E5% 95% 8F% E9% A1% 8C% E9% 9B% 86-1Z0-808 / dp / 4844339931) (commonly known as Kuromoto) Only one book. I think this is enough. In fact, from the mock exam questions at the end of the book, (almost) the same questions were asked many times.

After solving the problems in Chapters 1-9 to perfection, I solved the two mock exams at the end of the book. I read the explanation of the wrong question in the mock exam, and if I was still uneasy, I read the question and explanation of the relevant part from Chapter 1 to Chapter 9 and went around this book three times by the day.

Flow until the exam

I referred to this person's article. I haven't received any other vendor qualifications so I can't compare them, but it was quite annoying.

Exam day

I started at 13:30. Book your exam at a time when you can get the best performance from each. Enter the test site a little early, and after completing the reception procedure, the test will start. After solving 77 questions on the PC of the test center and reviewing it, I still had about an hour (the test time was two and a half hours), but I finished and left the venue. I received a pass / fail email from Oracle while walking from the venue to the station. Too early. The result was a pass with a correct answer rate of 78% (pass line is 65%).

Impressions

I tried to get a perfect score, but I had a problem that the coat color was different from that of Kuromoto, a problem that I could not pick up, and I was drunk by the air of the test center and dropped it considerably.

Where I personally studied for the exam and thought it was important

--Bool cannot be used in Java (not confused with C # etc.).

--The compiler implicitly rewrites the method expressions in the interface. Therefore, only public is allowed as the access modifier of the target method implementation in the subclass.

void test();
//↑ Before compilation ↓ After compilation
public abstract void test();

--If the processing in the constructor is not specified, the superclass constructor is implicitly called at the beginning without any arguments.

public class Test extends Sample{
	public Test(){
		System.out.println("test");
	}
}
/*↑ Before compilation ↓ After compilation*/
public class Test extends Sample{
	public Test(){
		//Call the default constructor of the Sample class
		super();
		System.out.println("test");
	}
}

--When you explicitly call the superclass constructor in the constructor, you must call it at the beginning.

public Test(){
	System.out.println("test");
	super("A"); //Compile error
}

--Access modifiers are in strict order private <none <protected <public

--When overriding, you must declare it with the same or looser access modifiers as the superclass method declaration without changing the signature.

public class Sample {
	protected void test(String name) {
		System.out.println(name);
	}
}

public class Test extends Sample {
	// protected,public is acceptable. No qualifier,private is a compile error
	public void test(String name) {
		super.test(name);
		System.out.println(name);
	}
}

--You cannot call an overloaded constructor after calling a superclass constructor.

at the end

Thank you for reading this far. If you find something wrong, I would appreciate it if you could point it out without mercy.