Albert Attard

Sorry if I was not clear.  Is there a template that I can follow when reposting such things, please?

Is this the right forum where we can raise potential errata about the OCP Oracle Certified Professional Java SE 17 Developer Study Guide: Exam 1Z0-829 book?

Hello.

With reference to section "Applying Unary Operators" in Chapter 2 (of the book OCP Oracle Certified Professional Java SE 17 Developer Study Guide: Exam 1Z0-829).

The unary plus operator (+) does not indicate whether a number is positive.  It promotes a variable to an int (https://docs.oracle.com/javase/specs/jls/se17/html/jls-15.html#jls-15.15.3).

Consider the following example.

public class Main {    public static void main(final String[] args) {        char a = 'A';        m(+a);    }    private static void m(int a) {        System.out.printf("I (%d) am an int%n", a);    }    private static void m(short a) {        System.out.printf("I (%d) am a short%n", a);    }    private static void m(byte a) {        System.out.printf("I (%d) am a byte%n", a);    }    private static void m(char a) {        System.out.printf("I (%s) am a char%n", a);    } }

The above example will print

I (65) am an int

You can try it with all other types (byte and short).

Hello,

With the risk of being pedantic - With reference to the section with title "Distinguishing between Primitives and Reference Types" (in the book OCP Oracle Certified Professional Java SE 17 Developer Study Guide: Exam 1Z0-829), it says that we cannot call methods on null objects (see attached image).

This is not 100% correct as we can call static methods on null objects as shown below.

public class Main {    public static void main(final String[] args) {        Thread a = null;        System.out.println(a.currentThread());    } }

Question 9, in the introduction chapter, shows the following module definition.

public module com.vet {   exports com.vet; }

Is this a valid, Java 17, model definition?  I am asking this question as the above does not compile and produces the following error.

/.../module-info.java:1: error: modifier public not allowed here public module com.vet {       ^ 1 error

The options available do not include compilation errors, as shown in the attached file.