o que é preciso para tirar uma certificação em java?

No caso, sua primeira certificação será a Java SE 8 Programmer I 1Z0-808.

Neste link: http://education.oracle.com/pls/web_prod-plq-dad/db_pages.getpage?page_id=5001&get_params=p_exam_id:1Z0-808
Tem bastante informação.

O preço hoje é 434,00 reais de acordo com a página acima.
O exame dura 150 minutos, tem 77 questões e a pontuação minima para passar é 65%.

De acordo com o site, os tópicos abordados são:

Java Basics

Define the scope of variables
Define the structure of a Java class
Create executable Java applications with a main method; run a Java program from the command line; including console output.
Import other Java packages to make them accessible in your code
Compare and contrast the features and components of Java such as: platform independence, object orientation, encapsulation, etc.
Working With Java Data Types

Declare and initialize variables (including casting of primitive data types)
Differentiate between object reference variables and primitive variables
Know how to read or write to object fields
Explain an Object's Lifecycle (creation, "dereference by reassignment" and garbage collection)
Develop code that uses wrapper classes such as Boolean, Double, and Integer.
Using Operators and Decision Constructs

Use Java operators; including parentheses to override operator precedence
Test equality between Strings and other objects using == and equals ()
Create if and if/else and ternary constructs
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

Create and use while loops
Create and use for loops including the enhanced for loop
Create and use do/while loops
Compare loop constructs
Use break and continue
Working with Methods and Encapsulation

Create methods with arguments and return values; including overloaded methods
Apply the static keyword to methods and fields
Create and overload constructors; including impact on default constructors
Apply access modifiers
Apply encapsulation principles to a class
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
Develop code that demonstrates the use of polymorphism; including overriding and object type versus reference type
Determine when casting is necessary
Use super and this to access objects and constructors
Use abstract classes and interfaces
Handling Exceptions

Differentiate among checked exceptions, unchecked exceptions, and Errors
Create a try-catch block and determine how exceptions alter normal program flow
Describe the advantages of Exception handling
Create and invoke a method that throws an exception
"Recognize common exception classes (such as NullPointerException, ArithmeticExcpetion, ArrayIndexOutOfBoundsException, ClassCastException)"
Working with Selected classes from the Java API

Manipulate data using the StringBuilder class and its methods
Creating and manipulating Strings
Create and manipulate calendar data using classes from java.time.LocalDateTime, java.time.LocalDate, java.time.LocalTime, java.time.format.DateTimeFormatter, java.time.Period
Declare and use an ArrayList of a given type
Write a simple Lambda expression that consumes a Lambda Predicate expression

[url]https://www.devmedia.com.br/forum/blog-preparatorio-para-certificacao-java-9-ocp/543621[/url]

Olhou o link? Esse é bom hein.

Pra quem gosta de certificação, basta pagar o exame e ler alguns "brain dumps" antes da prova. Eu, por exemplo, jamais contrato um programador baseado em ter ou não certificação.