Section 1
Preview this deck
Storage
Front
| 5 | 0 | ||
| 4 | 0 | ||
| 3 | 0 | ||
| 2 | 0 | ||
| 1 | 0 |
Active users
0
All-time users
0
Favorites
0
Last updated
6 years ago
Date created
Mar 1, 2020
Cards (61)
Section 1
(50 cards)
Storage
The hard drive of a computer, which acts as the long term storage unit. The slowest memory unit.
Memory
RAM, the third fastest memory in a computer that contains temporary data storage.
String
An object backed internally by a char array. Strings are immutable, because the arrays that back them are immutable. Whenever a change is made to a string, an entirely new String is created.
Java
A server-side language, used in the back-end of programming to interact with databases, serve up responses, etc. Not directly used in web browsers.
Java Inheritance
The mechanism in which one object acquires some or all of the variables and methods of another object. One of the Four Pillars of OOP.
finalize
An object class method that is called before the garbage collection for a particular object, used to release resources used by objects before they're removed from the memory.
JVM
Java Virtual Machine, an interpreter for compiled Java bytecodes.
final Keyword
Precedes the data type in a declaration of a constant, stating that an entity can only be assigned once, and its value can never be changed or overridden.
javac
To compile a Java source file, use the Java compiler called _______
OOP
Object Orientated Programming; the act of writing code as modules instead of as lists of instructions.
Composite Relationships
When an instance of one class has a reference to an instance in another class or in another instance of the same class. Also called an "Has-A" relationship, as class A "has-a" relationship to class B.
Polymorphism
The ability of an object to take on many forms. The most common use of this in OOP occurs when a parent class reference is used to refer to a child class object. Any Java object that can pass more than one IS-A test is considered to be this. In Java, all Java objects are this, since any object will pass the IS-A test for their own type and for the class Object.
equals(Object o)
Object class method that compares the memory addresses of two objects. Functionally equivalent to the == operator, unless overridden.
this
A special reserved reference variable in Java that refers to the current object and can call a constructor from another constructor within the same class.
Method Parameter
Information can be passed to methods as parameters, which act as variables inside the method.
int
A primitive data type that represents whole numbers. Reserves 32 bits of memory.
Method Overloading
The ability to define two or more different methods with the same name but different method parameters.
Java Class
A blueprint for creating objects of a certain kind; defines the state and behavior the objects will possess.
Runtime Exceptions
Errors that result from a logical error in a program.
Java Strings
A sequence of characters. Strings are immutable, meaning they are constant and cannot be changed once created. Strings are often recycled by the JVM.
Java Arrays
Arrays are objects that store multiple variables of the same type. However an Array itself is an object on the heap. Values in the Array are organized with an index of fixed size and type.
Java Compiler
Software that transforms Java code into instructions usable by the JVM
main
The method in the controlling class that is automatically executed when a Java application is run.
Java Access Modifiers:
Java provides a number of access modifiers to set access levels for classes, variables, methods and constructors. The four access levels are: Visible to the package. the default. No modifiers are needed. Visible to the class only (private). Visible to the world (public). Visible to the package and all subclasses (protected).
CPU Cache
Second fastest form of memory, the Cache is built into the CPU and acts as temporary data storage.
JDK
Java Development Kit. A software development environment for writing applets and application in Java .
Java Constructor
A special method used to initialize objects. The constructor is called when an object of a class is created. It can be used to set the initial values for the object's attributes.
Package
Used to group related classes. Like a folder in a file directory.
Double Class
Wraps a value of the primitive type 'double' in an object. An object of type Double contains a single field whose type is 'double'. In addition, this class provides several methods for converting a double to a String and a String to a double, as well as other constants and methods useful when dealing with a double.
Reference Variable
Stores (points to) the memory address of an object.
JRE
Java Runtime Environment; This allows you to execute Java programs, but it does not allow you to compile them.
finally Block
Always executes when the try block exits. This ensures that the finally block executes even if an unexpected exception occurs.
Method
A reusable block of code that is given a specific label. An object's method may change the object's state.
Register
The fastest form of memory, built into the CPU and used for temporary data storage.
java.lang
A special package in Java, is the default, implicitly imported into all Java classes. It contains many useful classes, including System and String.
Java Exceptions
Problems that arise during the execution of a program. When an Exception occurs, the normal flow of the program is disrupted and the program/Application terminates abnormally, which is not recommended, therefore, these exceptions are to be handled.
JPMS
Java Platform Module System; Collection of associated packages, resources, and a module descriptor.
Scanner Class
Provides convenient methods for reading input values of various types.
Contractual Members
A child class is guaranteed to have the public variables and methods of a super class, even if the implementations differ.
Object Class
The name of the Java class that is the "mother" of all objects. All other Java classes automatically inherit the Object class as the top-level parent class in the hierarchy. This class provides basic methods such as the toString, hashCode, and equals methods.
Checked Exceptions
An exception that is checked (notified) by the compiler at compilation time. These are exceptions that cannot be ignored, and the programmer should take care of (handle) them.
clone() method
An object method that creates a new instance of the class of current object and initializes all of its fields with exactly the contents of the corresponding fields of the object.
super Keyword
A keyword that can be used to invoke a parent class's method which has been overridden by the current subclass's method.
throws Keyword
Used in the signature of method to indicate that this method might throw one of the listed type exceptions. The caller to these methods then has to handle the exception using a try-catch block.
JIT Compilation
Just-In-Time Compilation; Compiles and translates the bytecode into machine code.
double Variable
Used to hold floating point values (values with decimal points).
IDE
Integrated Development Environment; a programming environment that includes an editor, compiler, and debugger.
throw Keyword
Used to explicitly throw an exception from a method or any block of code. Can throw either checked or unchecked exceptions. Used mainly to throw custom exceptions.
hashCode()
An object class method that is used to provide a unique numeric identifier for an object's contents in order to provide an alternate mechanism to loosely identify it. By default, it returns the internal memory address of the object.
Object
An instance of a class in memory.
Section 2
(11 cards)