Java 8 Questions for Oracle Certified Associate Java SE 8 Programmer 1 exam questions and answers

What year was the Java programming created 1995 What does OCA stand for Oracle Certified Associate What are the 2 tests for Java developers provided by Oracle OCA and OCP The full declaration of a method is called the method ____ signature True or False - can you add a multiline comment within a multiline comment? false How many public classes can be added to a single file 1 Write the syntax for the main method. public static void main(String[] args) When you compile a Java class what file type extension is output? .class What does a .class file contain bytecode True or false, what creating a public Java class in a file does the case used in the file name have to match the case used by the Java class name? true In a method declaration, the public, protected and private declarations are called what? access modifiers What is the one special package in Java that you don't need to import? What is the generic term for packages that are defined after the ny package? child packages When creating an array, which one of these definitions is correct? 1.) String[] args, 2.) String args[], 3.) String... args, 4.) all of the above 4 All of the above What package does the Files and Paths object belong to? What 2 common packages contain the Date class .Date and .Date If a class wanted to use the .Date class, but the class had imports for . and . which both contain the Date class how would you fix this? Add an explicit import for .Date since explicitly importing a class takes precedence over any wildcard imports. What command do you use to compile a Java class? javac What package is the ArrayList class in? . When defining a constructor for class Junk, what is the proper syntax? public Junk() { } // notice there is NO return value. What is a code block outside of a method called? instance initializer Given the class public class Junk { int eggs=0; public Junk() { eggs=1; } { eggs = 10; } } what is the value of eggs and why? Answer: 1 Reason: The value is 1 because the fields and instance initializers are run in the order they are declared and lastly the constructor is run. In the following code snippet, will this compile? public class Junk { { eggs = 6; } int eggs; } Why or why not? Answer: Won't Compile Reason: This will not compile because the instance initializer will try to set a field that hasn't been declared yet. What are the two types of data that Java applications contain? primitive type and reference types How many primitive data types does Java have? Answer: 8 There are 8 primitive data types: boolean, byte, short, int, long, float, double and char. What are the 8 Java primitive types? boolean, byte, short, int, long, float, double and char How many bits is an int primitive data type 32 bits How many bits is a long primitive data type? 64 bits Which of these floating point data types is bigger? float or double? Answer: double Reason: A double type is larger because it is 64 bits and float is only 32. How many bits is the char primitive type? Answer: 16 bits How many bits is a byte primitive data type Answer: 8 bits How many bits is a short data type? Answer: 16 bits When setting a float data type, what is the correct syntax? Answer: float myfloat = 123.456f Reason: You have to remember to add the trailing "f". What is the range of data a Java byte can hold Answer: -128 to 127 How many bits are used with the statement: int num; Answer: 32 What is the maximum number an int can hold Answer: 2,147,483,647 When declaring a literal number what type does Java assume the data is? Answer: int Reason: Java assumes the data is an int. If you want a really big number you have to add an "L" to the end to get a long. How would you define a literal binary number in Java? Answer: add the 0b prefix Reason: By adding 0b you can then add the binary values such as 0b11 How would you define a literal octal number in Java? Answer: add 0 prefix Reason: By adding a 0 prefix, you can define an octal number such as 017 which is equal to decimal 15. How would you define a literal hex value in Java? Answer: Add a 0x prefix Reason: By adding a 0x prefix, you can define a hex number. For example; 0x1F is 31. In Java 7, what feature was added to make numbers easier to read? An underscore option was created. int million = 1_000_000; the underscore cannot be first, before a decimal, after a decimal or at the end, but its OK elsewhere. Is the following statement valid? int value = null; Answer: No Reason: Primitive types cannot be set to null. As a general rule, all primitives start with: a.) lowercase b.) uppercase letters Answer: a. lowercase Reason: That's just the way it is. When declaring multiple variables on the same line what is the rule? You can declare as many as you want, but they have to be of the same type and separated by commas. String s1="hello", s2="world;