Strings, that are popular in Java development, are a series of figures. In the Java development language, strings are objects.

The Java s/w provides the String class to create and control strings.
Making Strings:

The most immediate manner to generate a string would be to compose:

Chain introduction = “HellO world!”;

public class StringDemo{

   public static void main(String args[]){
      char[] helloArray = { 'h', 'e', 'l', 'l', 'o', '.'};
      String helloString = new String(helloArray);  
      System.out.println( helloString );
   }
}

Whenever it strikes a string literal in your code, the compiler creates a String object with its value in this instance, "Hell O planet!'.

As to any item, it is possible to create String objects using the new key word and a constructor. The Chain class has eleven constructors that let you supply the first value of the string using different resources, including various characters.

Notice: The String class is immutable, therefore that once it's created a String item can not be altered. When there is a requirement to make lots of changes to Strings of figures, you then should use Chain Stream & Chain Contractor Groups.
Chain Span:

Procedures employed to get info about an item are called accessor methods. One accessor procedure that can be used with strings is the span() approach, which results the amount of figures within the chain thing.

Below specified application is a good example of span() , technique Chain type.

Below given program is an example of length() , method String class.

public class StringDemo {

   public static void main(String args[]) {
      String palindrome = "Dot saw I was Tod";
      int len = palindrome.length();
      System.out.println( "String Length is : " + len );
   }
}

This would produce the following result:

String Length is : 17

Concatenating Strings:

The String class includes a method for concatenating two strings:

string1.concat(string2);

This returns a new string that is string1 with string2 added to it at the end. You can also use the concat() method with string literals, as in:

"My name is ".concat("Zara");

Strings are more commonly concatenated with the + operator, as in:

"Hello," + " world" + "!"

which results in:

"Hello, world!"

Let us look at the following example:

public class StringDemo {

   public static void main(String args[]) {
      String string1 = "saw I was ";
      System.out.println("Dot " + string1 + "Tod");
   }
}

This would produce the following result:

Dot saw I was Tod

Creating Format Strings:

You have printf() and format() methods to print output with formatted numbers. The String class has an equivalent class method, format(), that returns a String object rather than a PrintStream object.

Using String’s static format() method allows you to create a formatted string that you can reuse, as opposed to a one-time print statement. For example, instead of:

System.out.printf("The value of the float variable is " +
                  "%f, while the value of the integer " +
                  "variable is %d, and the string " +
                  "is %s", floatVar, intVar, stringVar);

you can write:

String fs;
fs = String.format("The value of the float variable is " +
                   "%f, while the value of the integer " +
                   "variable is %d, and the string " +
                   "is %s", floatVar, intVar, stringVar);
System.out.println(fs);

String Methods:

Here is the list of methods supported by String class:

SN Methods with Description
1 char charAt(int index)

Returns the character at the specified index.

2 int compareTo(Object o)

Compares this String to another Object.

3 int compareTo(String anotherString)

Compares two strings lexicographically.

4 int compareToIgnoreCase(String str)

Compares two strings lexicographically, ignoring case differences.

5 String concat(String str)

Concatenates the specified string to the end of this string.

6 boolean contentEquals(StringBuffer sb)

Returns true if and only if this String represents the same sequence of characters as the specified StringBuffer.

7 static String copyValueOf(char[] data)

Returns a String that represents the character sequence in the array specified.

8 static String copyValueOf(char[] data, int offset, int count)

Returns a String that represents the character sequence in the array specified.

9 boolean endsWith(String suffix)

Tests if this string ends with the specified suffix.

10 boolean equals(Object anObject)

Compares this string to the specified object.

11 boolean equalsIgnoreCase(String anotherString)

Compares this String to another String, ignoring case considerations.

12 byte getBytes()

Encodes this String into a sequence of bytes using the platform’s default charset, storing the result into a new byte array.

13 byte[] getBytes(String charsetName

Encodes this String into a sequence of bytes using the named charset, storing the result into a new byte array.

14 void getChars(int srcBegin, int srcEnd, char[] dst, int dstBegin)

Copies characters from this string into the destination character array.

15 int hashCode()

Returns a hash code for this string.

16 int indexOf(int ch)

Returns the index within this string of the first occurrence of the specified character.

17 int indexOf(int ch, int fromIndex)

Returns the index within this string of the first occurrence of the specified character, starting the search at the specified index.

18 int indexOf(String str)

Returns the index within this string of the first occurrence of the specified substring.

19 int indexOf(String str, int fromIndex)

Returns the index within this string of the first occurrence of the specified substring, starting at the specified index

20 String intern()

Returns a canonical representation for the string object.

21 int lastIndexOf(int ch)

Returns the index within this string of the last occurrence of the specified character.

22 int lastIndexOf(int ch, int fromIndex)

Returns the index within this string of the last occurrence of the specified character, searching backward starting at the specified index.

23 int lastIndexOf(String str)

Returns the index within this string of the rightmost occurrence of the specified substring.

24 int lastIndexOf(String str, int fromIndex)

Returns the index within this string of the last occurrence of the specified substring, searching backward starting at the specified index.

25 int length()

Returns the length of this string.

26 boolean matches(String regex)

Tells whether or not this string matches the given regular expression.

27 boolean regionMatches(boolean ignoreCase, int toffset, String other, int ooffset, int len)

Tests if two string regions are equal.

28 boolean regionMatches(int toffset, String other, int ooffset, int len)

Tests if two string regions are equal

29 String replace(char oldChar, char newChar)

Returns a new string resulting from replacing all occurrences of oldChar in this string with newChar.

30 String replaceAll(String regex, String replacement

Replaces each substring of this string that matches the given regular expression with the given replacement.

31 String replaceFirst(String regex, String replacement)

Replaces the first substring of this string that matches the given regular expression with the given replacement.

32 String[] split(String regex)

Splits this string around matches of the given regular expression.

33 String[] split(String regex, int limit)

Splits this string around matches of the given regular expression.

34 boolean startsWith(String prefix)

Tests if this string starts with the specified prefix.

35 boolean startsWith(String prefix, int toffset)

Tests if this string starts with the specified prefix beginning a specified index.

36 CharSequence subSequence(int beginIndex, int endIndex)

Returns a new character sequence that is a subsequence of this sequence.

37 String substring(int beginIndex)

Returns a new string that is a substring of this string.

38 String substring(int beginIndex, int endIndex)

Returns a new string that is a substring of this string.

39 char[] toCharArray()

Converts this string to a new character array.

40 String toLowerCase()

Converts all of the characters in this String to lower case using the rules of the default locale.

41 String toLowerCase(Locale locale)

Converts all of the characters in this String to lower case using the rules of the given Locale.

42 String toString()

This object (which is already a string!) is itself returned.

43 String toUpperCase()

Converts all of the characters in this String to upper case using the rules of the default locale.

44 String toUpperCase(Locale locale)

Converts all of the characters in this String to upper case using the rules of the given Locale.

45 String trim()

Returns a copy of the string, with leading and trailing whitespace omitted.

46 static String valueOf(primitive data type x)

Returns the string representation of the passed data type argument.

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