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Java is, and is set to remain, the primary language for the professional programmer. There are 1.8 million Oracle Certified Developers and they earn more, 13.7% on average, than their non-certified colleagues. Here we look at the latest exams for Java Certification and how to prepare for them.
We were provided with three reasons for gaining solid expertise in Java by Simplilearn, whose training options are considered in detail later in this article:
- Java is the most popular programming language in use and is the only language that works across all computer and Android mobile platforms without needing to be recompiled for each one.
- Java is widely used for developing cutting-edge applications for web or mobile platform and acts as the stepping stone for anyone hoping to advance their career in mobile development.
- Excelling in Java also prepares you for a career in Big Data, as Hadoop (the most widely used framework of Big Data architecture) uses Java for design and development.
But why go the extra mile, with extra expense, of taking an exam and obtaining accreditation? To answer this question we went to Oracle University to see its responses to "What can an Oracle certification do for your?" The first is that it provides a competitive advantage as the knowledge you gain through training and practice will significantly expand you skill set and increase your credibility when interviewing for jobs. If you are already employed you can expect salary advancement. According to Oracle's 2012 salary survey, more than 80% of Oracle certified individuals reported a promotion, compensation increase or other career improvements as a result of becoming certified.
First rungs on the ladder
Java's core track of certifications starts with OCA - Oracle Certified Associate for which you need to pass Java SE 8 Programmer I, 1Z0-808. This exam is a prerequisite if you want to go on to OCP - Oracle Certified Professional for which you need to pass Java SE 8 Programmer II, 1Z0-809. Similarly gaining OCP status equips you to progress to OCE - Oracle Certified Expert and other higher level Java certifications. You can currently gain OCA and OCP certification with Java SE 7, but the exams for this retire at the end of 2018, so it is worth working toward the latest available.
Oracle exams are administered by Pearson VUE which has test centers in cities all over the world. The 1Z0-808 Exam consists of 77 multiple-choice questions and 1Z0-809 has 85. Both exams last 150 minutes and to pass you need a score of at least 65%. Each exam has a cost of $245 USD or the equivalent in local currency. However, some of the training options available bundle the exam.
The topics covered in Java SE 8 Programmer I are:
- Java Basics
- Compare and contrast the features and components of Java such as: platform independence, object orientation, encapsulation, etc
- Create executable Java applications with a main method; run a Java program from the command line; including console output
- Define the scope of variables
- Define the structure of a Java class
- Import other Java packages to make them accessible in your code
- Working With Java Data Types
- Declare and initialize variables (including casting of primitive data types)
- Develop code that uses wrapper classes such as Boolean, Double, and Integer.
- Differentiate between object reference variables and primitive variables
- Explain an Object's Lifecycle (creation, "dereference by reassignment" and garbage collection)
- Know how to read or write to object fields
- Using Operators and Decision Constructs
- Create if and if/else and ternary constructs
- Test equality between Strings and other objects using == and equals ()
- Use Java operators; including parentheses to override operator precedence
- Use a switch statement
- Creating and Using Arrays
- Declare, instantiate, initialize and use a one-dimensional array
- Declare, instantiate, initialize and use multi-dimensional array
- Using Loop Constructs
- Compare loop constructs
- Create and use do/while loops
- Create and use for loops including the enhanced for loop
- Create and use while loops
- Use break and continue
- Working with Methods and Encapsulation
- Apply access modifiers
- Apply encapsulation principles to a class
- Apply the static keyword to methods and fields
- Create and overload constructors; including impact on default constructors
- Create methods with arguments and return values; including overloaded methods
- Determine the effect upon object references and primitive values when they are passed into methods that change the values
- Working with Inheritance
- Describe inheritance and its benefits
- Determine when casting is necessary
- Develop code that demonstrates the use of polymorphism; including overriding and object type versus reference type
- Use abstract classes and interfaces
- Use super and this to access objects and constructors
- Handling Exceptions
- Create a try-catch block and determine how exceptions alter normal program flow
- Create and invoke a method that throws an exception
- Describe the advantages of Exception handling
- Differentiate among checked exceptions, unchecked exceptions, and Errors
- Recognize common exception classes (such as NullPointerException, ArithmeticException, ArrayIndexOutOfBoundsException, ClassCastException)
- Working with Selected classes from the Java API
- Create and manipulate calendar data using classes from java.time.LocalDateTime, java.time.LocalDate, java.time.LocalTime, java.time.format.DateTimeFormatter, java.time.Period
- Creating and manipulating Strings
- Declare and use an ArrayList of a given type
- Manipulate data using the StringBuilder class and its methods
- Write a simple Lambda expression that consumes a Lambda Predicate expression