{ }

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Java

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Easy

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Test results

String class

Method / Constructor	Description
`String(String str)`	Constructs a new String representing the same characters as `str`
`int length()`	Returns the number of characters
`String substring(int from, int to)`	Returns substring from index `from` up to (not including) `to`
`String substring(int from)`	Returns `substring(from, length())`
`int indexOf(String str)`	Returns index of first occurrence of `str`; `-1` if not found
`boolean equals(Object other)`	Returns `true` if same character sequence as `other`
`int compareTo(String other)`	Returns <0, 0, or >0 based on alphabetical ordering
`String[] split(String del)`	Splits the string around matches of `del`; returns a String array

Integer class

Method / Field	Description
`Integer.MIN_VALUE`	The minimum value representable by an `int`
`Integer.MAX_VALUE`	The maximum value representable by an `int`
`static int parseInt(String s)`	Returns the String argument as an `int`

Double class

Method	Description
`static double parseDouble(String s)`	Returns the String argument as a `double`

Math class

Method	Description
`static int abs(int x)`	Returns the absolute value of an `int`
`static double abs(double x)`	Returns the absolute value of a `double`
`static double pow(double base, double exponent)`	Returns `base` raised to the power of `exponent`
`static double sqrt(double x)`	Returns the nonnegative square root of `x`
`static double random()`	Returns a random double where `0.0 <= value < 1.0`

ArrayList class

Method	Description
`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`, shifting elements right
`E get(int index)`	Returns the element at position `index`
`E set(int index, E obj)`	Replaces element at `index` with `obj`; returns the old element
`E remove(int index)`	Removes element at `index`, shifting elements left; returns the removed element

Object class

Method	Description
`boolean equals(Object other)`	Returns `true` if this object is equal to `other`
`String toString()`	Returns a string representation of this object

File class

Constructor	Description
`File(String pathname)`	Constructs a File object from the given `pathname` string

Scanner class

Method / Constructor	Description
`Scanner(File f)`	Constructs a Scanner that reads from the given File
`int nextInt()`	Returns the next `int` from the input; throws `InputMismatchException` if unavailable or out of range
`double nextDouble()`	Returns the next `double` from the input; throws `InputMismatchException` if unavailable
`boolean nextBoolean()`	Returns the next `boolean` from the input; throws `InputMismatchException` if unavailable
`String nextLine()`	Returns the next line of text as a String; may return empty string if called immediately after another Scanner method
`String next()`	Returns the next token (whitespace-delimited) as a String
`boolean hasNext()`	Returns `true` if there is another token to read; `false` otherwise
`void close()`	Closes this scanner