OCA_1Z0-808_Module00_Introduction_Java.pptx

Oracle Java SE 8
Programmer I
Certification
Exam 1Z0-808
OPENING REMARKS

ABBREVIATIONS & ACRONYMS
2
actype – actual object’s type at run time
assop – assignment operator
castype – data type specified inside the parens for an explicit
cast
comperr – compilation error
ctor – constructor
dim – dimension
initer – initializer
op – operator
paramlist – list of formal parameters in a lambda expression
preditype – data type specified inside the angle brackets
reftype – reference type
refvar – reference variable
sout – any printing statement such as System.out.println(),
etc.
stat – statement
ternop – ternary operator
var – variable
AIOOBE – ArrayIndexOutOfBoundsException
CCE – ClassCastException
ChE – checked exception
CSR – the Catch-or-Specify Requirement
DTPE – DateTimeParseException
E – an exception (regardless of the type)
IAE – IllegalArgumentException
IOE – IOException
IOOBE – IndexOutOfBoundsException
LDT – any of the new date/time classes in Java 8
LOC – line of code
NFE – NumberFormatException
NPE – NullPointerException
RTE – RuntimeException
SIOOBE – StringIndexOutOfBoundsException
TCF – try-catch-finally construct
Igor Soudakevitch  2019
igor.soudakevitch@mail.ru

KNOW YOUR
ENEMY
3
1
Up Close and Personal

“The certification is designed for beginners
in programming and/or those with a
nonprogramming background who have
basic mathematical, logical, and analytical
problem-solving skills and who want to
begin to learn the Java programming
language at an introductory level…
4
4

Fix This (Java Magazine, July-Aug 2015, pp.14-15)
5
Given this code fragment from file Cart.java:
package shop;
// line n1
{ Cart() {

TEST STRUCTURE
Core
70-80%
Non-random
Advanced
Random
(Tough/Very Tough
in Enthuware)
Guinea Pigs
Average
Not graded
6
– 80 Qs, 150 minutes, 65% passing
score
– 42 Exam Topics in 9 groups (ref.to Oracle Univ)
QUESTIONS

GETTING USED TO EXAM ENVIRONMENT
7
What to expect in a Pearson VUE test center:
https://home.pearsonvue.com/test-taker/security.aspx

TRICKS OF THE TRADE
8
Right-clicking eliminates options
Saving up to TEN Minutes:
"I Accept"  10m  2h30m countdown
“If there’s a particular facet of the Java language that you have
difficulty remembering, try memorizing it before the exam and
write it down as soon as the exam starts.”
– B&S: acceptable types in switch
– list of modifiers
– operator precedence chart
– ‘popular’ ChEs & RTEs + NPE throwing scenarios
MERELY
A SUGGESTION

TRICKS OF THE TRADE, cont’d
9
– code is pretty-typed  do NOT count curly braces
– ‘straight arrows’, ‘curved balls’ & ‘caltrops’ w/‘red herrings’:
Given in the file HiThere.java:
class HiThere {
public static void main(String[] args) {
System.out.print("Hi there" + args[0]);
}
}
Which set of commands prints Hi there! in the console?
A. javac HiThere C. javac HiThere.java !
java HiThere ! java HiThere
B. javac HiThere.java D. javac HiThere.java
java HiThere ! java HiThere.class !

10
List<Integer> l = new ArrayList<>();
l.add(42);
l.add(null);
for (int i = 0; i<l.size(); i++) System.out.print(l.get(i)); // line 1
for (Object i : l) System.out.print(i); // line 2
for (int i : l) System.out.print(i); // line 3
Given:
int a = 0;
String str = new String("Yell");
str = str.replace("Yell", "Hell");
str = str.insert(4,"o");
if ("Hello" == str && a++ == 0) str = null;
System.out.println(a);
What is the result?
A. The code prints 1
B. The code prints 0
C. Compilation fails
D. The code throws an exception at run time

11
 Don’t jump to the code. Read – the question – first. Force yourself to read it.
 Give the problem your best shot at the very first pass.
 Do it unhurriedly and never let yourself re-read what you’ve already read carefully.
 Take the code at its face value. Not every snippet is meant to deceive you.
 No cherry picking; do the questions as they come in.
 Treat your Review marks as gold.
 Trust your gut feelings.
 Resist the temptation to redo calculations right away, leave it for the Review.

12
Overarching Rule:
Read the question first, then options and then code carefully. Subvocalize, even.
int[][] arr2D = new int[][] { { 0, 1, 2, 3 } { 4, 5 } };
 The most ‛obvious’ choice just may be booby-trapped;
 Never assume that the exam creators made a mistake;
 Weird looking, overly complex code is likely to contain:
• out-of-scope vars;
• invalid syntax;
• unreachable stats;

STUDY
ENVIRONMENT
Enhancements
13
2

SETTING UP STUDY ENVIRONMENT
14
Windows Registry Editor Version 5.00
[HKEY_CLASSES_ROOT*shellRun with Java]
[HKEY_CLASSES_ROOT*shellRun with Javacommand]
@="C:JCRWJ.bat %1"
Beating
heart:
javac %1
java %~n1
package org.xlator;
public class HelloWorld{
System.out.println("Hello, hello...");
}}

SETTING UP STUDY ENVIRONMENT,
cont’d
15
In file ClassA.java (to be located in C:Try_Javatempa):
package tempa;
public class ClassA{
public String name;
public ClassA(){
name = this.getClass().getSimpleName(); }
public ClassA(String name) { this.name = name; }
}
In file ClassB.java (in C:Try_Javatempb):
package tempb;
import tempa.*;
public class ClassB extends ClassA{
public ClassB(String name){ super(name); }
}
In file MyClass.java (in C:Try_Javaorgxlator):
package org.xlator;
import tempa.*;
import tempb.*;
public class MyClass {
ClassA ca = new ClassA();
ClassB cb = new ClassB("ClassB");
System.out.println(ca.name + ", " + cb.name + ", " + args[1]); }
}

10 min TRICK TABLES
Memorization Technique
16
3

JAVA MODIFIERS (extract)
17
MNEMONICS
LHS: (pa-pri-pro-pu & a-f-s) RHS: ‘CIC Me Data’ (click/kick) : A-O
Four Crosses Island Lonely Star The Ramp of Doom

JAVA MODIFIERS, cont’d
18
(in file I6.java)
interface I1 {}
// private interface I2 { } // INVALID
// protected interface I3 { } // INVALID
// final interface I4 { } // INVALID
// static interface I5 { } // INVALID
public interface I6 { }
abstract interface I7 { } // abstract keyword is redundant
(in file C6.java)
class C1 { }
// private class C2 { } // INVALID
// protected class C3 { } // INVALID
final class C4 { }
abstract class C5 { abstract void run5(); }
public class C6 {
int a;
private int b;
protected int c;
public int d;
static int e;
final int f = 0;
// abstract int g; // INVALID
private class C7 { } //
protected class C8 { } // all six are VALID
static class C9 { } // but inner classes and interfaces
private interface I8 { } // are not on the 1Z0-808 exam
protected interface I9 { } //
static interface I10 { } //
// final interface I11 { } // INVALID
cont’d:
C6(){ }
private C6(int a){ }
protected C6(int a, int b){ }
public C6(int a, int b, int c){ }
// abstract C6(){ } // INVALID
// final C6(){ } // INVALID
// static C6(){ } // INVALID
void run1(){
int a;
final int f;
// private int b; // INVALID
// protected int c; // INVALID
// public int d; // INVALID
// static int e; // INVALID
// abstract int h; // INVALID
}
private void run2(){ }
protected void run3(){ }
public void run4(){ }
}
One and only! 

JAVA MODIFIERS, cont’d
19
 static entities belong to the class;
 interfaces cannot be final;
 no abstract ctors;
 no static ctors;
 no final ctors;
 only final inside methods, ctors or initers;
 sneaky ctors: static & non-static semantics.
SUGGESTED PATTERN TO MEMORIZE
QUESTION: What about abstract static void run() ? is it possible? and why?

PRIORITY OF OPERATORS
20
1 of 2
FULL FORM

PRIORITY OF OPERATORS, cont’d
21
2 of 2
FULL FORM

PRIORITY OF OPERATORS, cont’d
22
 postfix / prefix increment / decrement operators are of the top
priority;
 all arithmetic ops including comparison come before equality testing;
 assignment, including its compound forms, is of the lowest priority.
TO MEMORIZE:

ASSUMPTIONS
23
 Missing package and import statements:
If sample code does not include package or import statements, and the
question does not explicitly refer to these missing statements, then assume
that all sample code is in the same package, and import statements exist to
support the code.
Typical; used in most of the questions that use core Java classes outside of
java.lang such as java.io.IOException, java.util.List,
java.util.function.Predicate and so on.
Source: Oracle Univ.

ASSUMPTIONS, cont’d
24
 No file or directory path names for classes:
If no file names or directory locations of classes  assume one of the
following, whichever enables the code to compile and run:
– All classes are in one file;
– Each class is contained in a separate file, and all files are in one directory.
Also quite common.

25
 Unintended line breaks:
Sample code may have unintended line breaks. If you see a line of code
that looks like it has wrapped, and this creates a situation where the
wrapping is significant (for example, a quoted string literal has wrapped),
assume that the wrapping is an extension of the same line, and the line
does not contain a hard carriage return that would cause a compilation
failure.
Didn’t meet this one; all code is pretty-typed.

26
 Code fragments:
A code fragment is a small section of source code that is presented without
its context. Assume that all necessary supporting code exists and that the
environment fully supports the correct compilation and execution of the
code shown and its omitted environment.
A good half of the questions contains such code fragments.

27
 Descriptive comments:
Take descriptive comments, such as "setters and getters go here," at face
value. Assume that correct code exists, compiles, and runs successfully to
create the described effect.
Met it once, in the form “setter and getter methods go here”.

WORD OF CAUTION
28
WEB RESOURCES: heavy reliance not advisable
“For convenience, the Java compiler automatically imports three entire packages for
each source file: (1) the package with no name, (2) the java.lang package, and (3) the
current package (the package for the current file).”
Current JLS8 (Chapter 7, Packages, preamble):
A package consists of a number of compilation units. A compilation unit automatically
has access to all types declared in its package and also automatically imports all of
the public types declared in the predefined package java.lang.”
NB

STUDY TIPS & SUGGESTIONS
29
 Keep a written record of your errors;
 Start and finish your day by going through this list of failures;
 Use colors, invent mnemonic formulas;
 Draw pictures on paper and in your mind;
 Do not worry much about the ‘Extra’ stuff;
 Concentrate instead on the ‘Core’ rules because…
…you will encounter something very close to them on the exam.

REMINDER: THE ‘QUOC’ PRINCIPLE
30
questio
n
options code

OCA_1Z0-808_Module00_Introduction_Java.pptx

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