Oracle Java Foundations study guide

Oracle Java Foundations · Work through your exam, one topic at a time.

The Oracle Certified Foundations Associate, Java credential - associated with exam code 1Z0-811 - is Oracle's entry-level Java certification. It is aimed at people who are starting out with the language: students, career changers, and developers who want a structured, vendor-recognized benchmark for fundamental Java knowledge before moving on to professional-level certification. The Oracle Java Foundations study guide has 9 sections and about 3,077 words.

Java Basics

A Java source file ends in .java and may declare at most one public top-level type. If it does, the file name must match that type exactly, including case.

345 words, about 2 min 02

Working with Java Data Types

byte (8 bits, -128..127), short (16), int (32), long (64), float (32), double (64), char (16-bit unsigned, 0..65535), and boolean . Each primitive has a wrapper: Byte , Short , Integer , Long , Float , Double , Character , Boolean .

338 words, about 2 min 03

Using Operators and Decision Constructs

Division of two integers truncates toward zero, and the sign of % follows the left operand ( -7 % 3 is -1 ). Post-increment returns the old value, pre-increment the new one: int x = 5; int y = x++ + x; yields y = 11 with x = 6 .

383 words, about 2 min 04

Creating and Using Arrays

int[] a = new int[3]; creates three elements with default values ( 0 , or null for object arrays). int a[] also compiles but int[] a is preferred.

334 words, about 2 min 05

Using Loop Constructs

while tests the condition before the first iteration, so the body may run zero times. do-while tests after, so the body always runs at least once and ends with a semicolon.

367 words, about 2 min 06

Working with Methods and Encapsulation

Every method declares a return type or void ; modifier order is free. Overloading means the same name with a different parameter list (count, types, or order).

352 words, about 2 min 07

Working with Inheritance

A class extends exactly one superclass; interfaces may extend several. Every class ultimately extends Object .

346 words, about 2 min 08

Handling Exceptions

Throwable splits into Error (serious JVM problems, not normally caught) and Exception . RuntimeException and its subclasses are unchecked; every other Exception is checked and must be caught or declared with throws .

311 words, about 2 min 09

Working with Selected Classes from the Java API

String is immutable - every "modifying" method returns a new object. == compares references, so use equals / equalsIgnoreCase for content, and compareTo for ordering.

301 words, about 2 min