Java Quick Reference
Accessible methods from the Java library that may be included in the exam
Class Constructors and Methods Explanation
String Class
String(String str) Constructs a new String object that represents the same sequence of
characters as
str
int length()
Returns the number of characters in a String object
String substring(int from,
int to)
Returns the substring beginning at index from and ending at index to - 1
String substring(int from)
Returns substring(from, length())
int indexOf(String str)
Returns the index of the rst occurrence of str; returns -1 if not found
boolean equals(String other) Returns true if this is equal to other; returns false otherwise
int compareTo(String other) Returns a value <0 if this is less than other; returns zero if this is
equal to
other; returns a value >0 if this is greater than other
Integer Class
Integer(int value) Constructs a new Integer object that represents the specied int value
Integer.MIN_VALUE The minimum value represented by an int or Integer
Integer.MAX_VALUE
The maximum value represented by an int or Integer
int intValue()
Returns the value of this Integer int
Double Class
as an
Double(double value) Constructs a new Double object that represents the specied double value
double doubleValue() Returns the value of this Double as a double
Math Class
Returns the absolute value of an int value
Returns the absolute value of a double value
Returns the value of the rst parameter raised to the power of the second
parameter
Returns the positive square root of a double value
Returns a double value greater than or equal to 0.0 and less than 1.0
ArrayList Class
int size()
Returns the number of elements in the list
boolean add(E obj) Appends obj to end of list; returns true
void add(int index, E obj)
Inserts obj at position index (0 <= index <= size), moving
elements at position
index and higher to the right (adds 1 to their indices) and
adds 1 to size
E get(int index) Returns the element at position index in the list
E set(int index, E obj) Replaces the element at position index with obj; returns the element
formerly at position
index
E remove(int index)
Removes element from position index, moving elements at position
index + 1 and higher to the left (subtracts 1 from their indices) and subtracts 1
from size; returns the element formerly at position
index
Object Class
boolean equals(Object other)
String toString()
00762-118-CED-CSA_Appendix.indd 209 4/12/19 8:50 PM
AP Computer Science A Course and Exam Description
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Appendix V.1
|
209
static int abs(int x)
static double abs(double x
)
static double pow(double
base, double exponent)
static double sqrt(double x)
static double random()
