Standard Java Library Methods Required for AP CS A

Accessible Methods from the Java Library That May Be Included on the Exam
class java.lang.Object

• boolean equals(Object other)
• String toString()

class java.lang.Integer

• Integer(int value)
• int intValue()
• Integer.MIN_VALUE // minimum value represented by an int
• Integer.MAX_VALUE // maximum value represented by an int

class java.lang.Double

• Double(double value)
• double doubleValue()

class java.lang.String

• int length()
• String substring(int from, int to) 
  // returns the substring beginning at from
  // and ending at to-1
• String substring(int from)
  // returns substring(from, length())
• int indexOf(String str)
  // returns the index of the first occurrence of str;
  // returns -1 if not found
• int compareTo(String other) 
  // returns a value < 0 if this is less than other
  // return a value = 0 if this is equal to other
  // return a value > 0 if this is greater than other

class java.lang.Math

• 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()
  // returns a double in the range [0.0, 1.0)

​class java.util.List<E>

• int size()
• boolean add(E obj)
  // appends obj to the 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 adjusts size
• E get(int index)
• E set(int index, E obj)
  // replaces the element at position index, with obj
  //returns the element formerly at the specified position
• 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 adjusts size
  // returns the element formerly at the specified position
• class java.util.ArrayList implements java.util.List