A particular way of organizing data in our programs.
An object is a single instance of a Java class. An object has both state and behavior.
Primitive types are the basic, simple data types that are inherent to Java (int, double, char, and boolean)
A data structure that stores a **fixed** number of elements, all of the same type, one after another like a list.
The position of an element in an array. The first element is at index 0, the second element is at index 1, and so on.
Getting a value at a particular index in an array.
The number of elements an array can hold. You can get the length of an array `arr` by typing `arr.length`
A for loop lets us repeat code a **fixed number of times**.
An exception is thrown by Java when a **runtime error** is encountered. The exception provides information about what kind of error occurred.
When an object is assigned to a variable, the variable doesn't hold all of the object's data, it only holds a *pointer* to the object's data. The variable holds a memory location (think of it as a pointer to that memory location), and the object data is stored at that memory location.
Looping through all of the elements of an array
A class is a template, or a blueprint, from which Java objects are created. All Java programs start with a class.
Related classes are grouped together into packages.
ArrayList is a Java class that is like an Array with extra powers. It can automatically resize and comes with other helpful methods.
A for loop that is written differently so that it loops through each element in a data structure, as opposed to having a loop counter variable that goes from 0 to length-1.
A Java Interface that represents a general List. The interface provides a list of methods that classes should implement if they want to be used as a List.
A method is a way to teach the computer a new command
An interface provides a list of methods that *must* be defined if a class chooses to implement the interface.
Declaring a variable is defining it for the first time.
Initializing a variable is giving it an initial value, or a starting value.
A 2D Array is an array of arrays, used to represent tables, grids, and matrices.
The ordering of 2D arrays is row-major order, meaning the first index is the row, and the second index is the col. `arr[2][0]` would access the element on the third row and first column.
A for loop written, or “nested”, inside of another for loop. For example:
A data structure that stores key -> value mappings.
A key is the value used to look something up in a HashMap
The value is the result you get when you look up a key in a HashMap. It is the value paired with a key.
A number system defines how we represent numbers. It defines which digits we can use, and what value each position (place value) in a number has.
The binary number system is the Base 2 Number System. It is a number system that only uses 2 digits (0 and 1).
The decimal number system is the Base 10 number system. It is a number system that only uses 10 digits (0 through 9).
The number base of a number system defines how many digits are in the number system, and the base of the exponent for each place value in a number.
The octal number system is the Base 8 number system. It is a number system that only uses 8 digits (0 through 7).
The hexadecimal number system is the Base 16 number system. It is a number system that only uses 16 digits (0 1 2 3 4 5 6 7 8 9 A B C D E F)
Bit means "binary digit". A bit is a single digit in a binary number. A bit can either be 0 or 1.
A byte is 8 bits.
A kilobyte (kB) is 2^10 bytes (1024 bytes) of binary data.
A megabyte (MB) is 2^20 bytes (1024 kB) of binary data.
A gigabyte (GB) is 2^30 bytes (1024 MB) of binary data.
The way your code is written is the style. It covers the aspects of the code that goes beyond whether or not it just works.
A control structure lets us change the flow of the code.
Top down design is a method for breaking a problem down into smaller parts.
A specific standard for commenting Java programs. Javadoc is a format to follow when commenting in order to clearly explain your code.
A method called on the Class, rather than on a specific object of the Class.
Programming model that focuses on **objects** and the data and actions associated with the objects.
The state of an object is all of the object's associated data. It is the *state* that the object is in.
The behavior of an object is what the object is able to do. It is the actions that can be performed by the object.
Instance is what you call a specific object constructed from a class. Instance and object generally refer to the same thing. An object is a specific instance of a class.
A variable defined in a Class, for which each object of the class has its own copy.
An instance method is a method that defines the behavior of an object. It defines an action that the object can perform.
A variable or attribute of a class that is shared between **all** instance of a class. Each instance **does not** get their own copy.
A constant is a variable you define at the top of the program that doesn’t change. The reason to define constants is to store named variables that have relevant values for the program.
