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Java in a Nutshell

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The java.lang Package

25.57 java.lang.String (JDK 1.0)

The String class represents a string of characters. A String object is created by the Java compiler whenever it encounters a string in doublequotes--this method of creation is usually simpler than using a constructor. A number of the methods of this class provide useful string manipulation functions. length() returns the number of characters in a string. charAt() extracts a character from a string. compareTo() compares two strings. equalsIgnoreCase() tests string for equality, ignoring case. startsWith() and endsWith() compare the start and end of a string to a specified value. indexOf() and lastIndexOf() search forward and backwards in a string for a specified character or substring. substring() returns a substring of a string. replace() creates a new copy of the string with one character replaced by another. toUpperCase() and toLowerCase() convert the case of a string. trim() strips whitespace from the start and end of a string. concat() concatenates two strings, which can also be done with the + operator.

Note that String objects are immutable--there is no setCharAt() method to change the contents. The methods above that return a String do not modify the string they are passed, but instead return a modified copy of the string. Use a StringBuffer if you want to manipulate the contents of a string, or use toCharArray() to convert a string to an array of char values.

The static valueOf() methods convert various Java primitive types to strings.

public final class String extends Object implements Serializable {
    // Public Constructors
            public String();
            public String(String value);
            public String(char[] value);
            public String(char[] value, int offset, int count);
        #   public String(byte[] ascii, int hibyte, int offset, int count);
        #   public String(byte[] ascii, int hibyte);
        1.1public String(byte[] bytes, int offset, int length, String enc) throws UnsupportedEncodingException;
        1.1public String(byte[] bytes, String enc) throws UnsupportedEncodingException;
        1.1public String(byte[] bytes, int offset, int length);
        1.1public String(byte[] bytes);
            public String(StringBuffer buffer);
    // Class Methods
            public static String copyValueOf(char[] data, int offset, int count);
            public static String copyValueOf(char[] data);
            public static String valueOf(Object obj);
            public static String valueOf(char[] data);
            public static String valueOf(char[] data, int offset, int count);
            public static String valueOf(boolean b);
            public static String valueOf(char c);
            public static String valueOf(int i);
            public static String valueOf(long l);
            public static String valueOf(float f);
            public static String valueOf(double d);
    // Public Instance Methods
            public char charAt(int index);
            public int compareTo(String anotherString);
            public String concat(String str);
            public boolean endsWith(String suffix);
            public boolean equals(Object anObject);  // Overrides Object
            public boolean equalsIgnoreCase(String anotherString);
        #   public void getBytes(int srcBegin, int srcEnd, byte[] dst, int dstBegin);
        1.1public byte[] getBytes(String enc) throws UnsupportedEncodingException;
        1.1public byte[] getBytes();
            public void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin);
            public int hashCode();  // Overrides Object
            public int indexOf(int ch);
            public int indexOf(int ch, int fromIndex);
            public int indexOf(String str);
            public int indexOf(String str, int fromIndex);
            public native String intern();
            public int lastIndexOf(int ch);
            public int lastIndexOf(int ch, int fromIndex);
            public int lastIndexOf(String str);
            public int lastIndexOf(String str, int fromIndex);
            public int length();
            public boolean regionMatches(int toffset, String other, int ooffset, int len);
            public boolean regionMatches(boolean ignoreCase, int toffset, String other, int ooffset, int len);
            public String replace(char oldChar, char newChar);
            public boolean startsWith(String prefix, int toffset);
            public boolean startsWith(String prefix);
            public String substring(int beginIndex);
            public String substring(int beginIndex, int endIndex);
            public char[] toCharArray();
        1.1public String toLowerCase(Locale locale);
            public String toLowerCase();
            public String toString();  // Overrides Object
        1.1public String toUpperCase(Locale locale);
            public String toUpperCase();
            public String trim();

Passed To:

Many methods

Returned By:

Many methods

Type Of:

BorderLayout.CENTER, BorderLayout.EAST, BorderLayout.NORTH, BorderLayout.SOUTH, BorderLayout.WEST, File.pathSeparator, File.separator, Font.name, HttpURLConnection.method, HttpURLConnection.responseMessage, InvalidClassException.classname, StreamTokenizer.sval, StringBufferInputStream.buffer

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