Java Tutorial Index

Java Tutorial Java Features C++ vs Java Java History Java Hello World Java Development Kit Java Runtime Environment Java Virtual Machine Difference between JDK, JRE, and JVM Memory Areas in Java Java Operators Java Keywords Primitive Data Types Variables

Java Loops

Java Do While Loop Java While Loop Java For Loop Java Enhanced For Loop

Java Programs

Java Basic Programs Factorial Program in Java Fibonacci Series Program in Java Prime Number Program in Java Palindrome Number Program in Java Armstrong Number Program in Java Anagram Program in Java Pattern Programs in Java Calculator Program in Java Leap Year Program in Java Addition Program in Java Number Pattern Programs in Java Star Pattern Programs in Java Package Program in Java Pyramid Program in Java Sorting Program in Java String Palindrome Program in Java Even Odd Program in Java For Loop Program in Java If Else Program in Java Switch Case Program in Java GCD Program in Java LCM Program in Java Hello Program in Java Matrix Program in Java Menu Driven Program in Java Series Program in Java Client Server Program in Java Swapping Program in Java Pig Latin Program in Java Tower of Hanoi Program in Java Recursion Program in Java Matrix Multiplication Program in Java Perfect Number Program in Java Classes and Objects in Java Example Programs String Programs in Java Array Programs in Java Constructor Program in Java Inheritance Program in Java Abstract class Program in Java Interface Program in Java Encapsulation Program in Java Polymorphism Program in Java Exception Handling Program in Java Multithreading Program in Java Thread Program in Java Collection Programs in Java ArrayList Program in Java Stack Program in Java Applet Program in Java Swing Program in Java JDBC Program in Java Program to find and replace characters on string in java Program to find the duplicate characters in a string Program to check whether a given character is present in a string or not Java Program to Print Permutations of String Java program to find frequency of characters in a string Java Program to remove duplicate characters in a string Java Program to Sort an Array of 0's, 1's, and 2’s | Dutch National Flag Problem in Java Java Program to print even and odd numbers using 2 threads Java Program to generate binary numbers Java program to count the occurrences of each character Java Program to Add Digits Until the Number Becomes a Single Digit Number Program to Implement FLAMES Game in Java Packages Program in java Pangram Program in Java Java program to print matrix in Z form CRC Program in Java Star Program in Java Structure of Java Program RMI program in Java Caesar Cipher Program in Java Java Programming certification Round Robin Scheduling Program in Java Java Program to find the smallest element in a tree Program to Find Square Root of a Number Without sqrt Method in Java Program to Find the Common Elements between two Arrays in Java Automorphic Number Program in Java

Java Sorting

Sorting Algorithms in Java Merge Sort in Java Quick Sort in Java Bubble Sort in Java Insertion Sort in Java Selection Sort in Java Heap Sort in Java Radix Sort in Java Topological Sort in Java Bucket Sort in Java Counting Sort in Java Java Program to Create Set of Pairs Using HashSet

Java OOPs Concepts

OOPs - Object Oriented Programming Objects and Classes in Java Methods in Java Java Naming Conventions Constructors in Java Java this keyword Java static keyword Inheritance in Java Aggregation in Java Java super keyword Constructor Chaining and Constructor Overloading Java Polymorphism Static and Dynamic Binding in Java Java Abstraction Abstract class in Java Interface in Java Difference between Abstract class and Interface Java final keyword Packages in Java Access Modifiers in Java Java Wrapper classes Java Numbers Java Characters Java Integer Java Boolean Java Arrays Java Command Line Arguments Java strictfp Keyword Java Enumeration Java Math

Java Strings

Java Strings Java String Methods StringBuilder in Java StringBuffer in Java Java Regular Expressions StringBuffer vs StringBuilder String vs StringBuffer String vs StringBuilder String Manipulation in Java Java String Concatenation How to Reverse a String in Java String Array in Java How to Compare Two Strings in Java How to Concatenate Two Strings in Java Why String in Immutable in Java java.lang.NumberFormatException for Input String String Pool in Java Java Generate Random String How to take String Input in Java Java String Interview Questions

Java Exceptions

Exception Handling in Java Java try catch Java throw Java throws Difference between throw and throws Java finally Java Custom Exception Java Exception Propagation

Garbage Collection

Automatic Resource Management in Java Java Garbage Collection Java finalize() Java gc() Difference between final, finally and finalize Java Garbage Collection Interview Questions


Multithreading in Java Process and Thread in Java Basic Terms in Multithreading Java Thread creation Thread Scheduler in Java Java Thread class DeadLock in Java

Java IO

Java IO Java Read File Java file Reader Java Buffer Reader Java file Writer Java BufferedWriter Java InputStreamReader Scanner in Java Java StringReader Java StringReader Class Java StringWriter Class Java PrintWriter Java File Java Read File Line By Line Java FileInputStream Java FileOutputStream Java Create File Java Delete File Java Open File Java Read File to String Java copy file Jar File in Java Java FileNotFoundException


Java Serialization Java transient


Java Network Programming Java Socket Programming Java URL Java URLConnection HttpURLConnection in Java Java InetAddress Java DatagramSocket and Java DatagramPacket


Java AWT


Swing in Java

Java Collections

Collections in Java Java List Interface ArrayList in Java LinkedList in Java Vector in Java Stack in Java ArrayList vs LinkedList in Java ArrayList vs Vector in Java Java Set Interface HashSet in Java LinkedHashSet in Java TreeSet in Java Java Queue Interface PriorityQueue in Java Deque in Java ArrayDeque in Java Java Map Interface HashMap in Java LinkedHashMap in Java TreeMap in Java Dictionary in Java Hashtable in Java Properties in Java Collections class in Java Java Comparable Java Comparator Comparable vs Comparator in Java

Java Generics

Generics in Java

Java Annotations

Annotations in Java


Java JDBC Tutorial JDBC Architecture Types of JDBC Drivers JDBC vs ODBC Java Database Connectivity with MySQL Java Database Connectivity with Oracle Statements in java Prepared statement in Java Resultset in java Java ResultSetMetaData DatabaseMetaData in Java Callable Statement in Java Transaction Management in Java Design of JDBC

Java Differences

Java vs DotNET Java vs JavaScript Kotlin vs Java Java vs C++ C# vs Java Java float vs double Java vs Scala Java vs Go Java vs Golang Java Extends vs Implements Java vs Node.js Static vs Non-static in Java int vs Integer in Java Java protected vs private Java vs Dot Net Stack vs Heap in Java Java Array vs ArrayList Java SE vs EE Class vs Object in Java Java vs Bedrock Difference between = = and equals ( ) in java Difference between C, C++, java HashMap Vs HashTable Checked vs Unchecked Exceptions in Java Difference between print() and println() in Java Differences between Lock and Monitor in Java Concurrency Differences between Set and List in Java Char and String differences in Java Difference between String, StringBuffer and StringBuilder in java Difference between String and Char Array in Java Differences between Byte Code and Machine Code Difference between String Tokenizer and split Method in Java Difference between JIT and JVM in Java Difference Between Data Hiding and Abstraction in Java Difference Between BufferedReader and FileReader Difference Between Thread.start() and Difference between Aggregation and Composition in Java Difference between Constructor and Method in Java Difference between next() and nextline() in Java Difference between Static and Instance Methods in Java Differences and Similarities between HashSet, LinkedHashSet and TreeSet in Java Different Ways to Print Exception Message in Java Different Ways to Take Input from User in Java Difference Between Access Specifiers and Modifiers in Java Difference Between Java and PHP Difference Between replace() and replaceall() in Java Difference between this and super in Java Generics vs Wildcard in Java

How to

How to convert String to String array in Java How to find length of integer in Java How to get Day Name from Date in Java How to open the Java control panel How to resolve Illegal state exceptions in Java How to reverse a linked list in java How to encrypt password in Java How to calculate time complexity of any program in Java How to check version of java in Linux How to enable java in chrome How to run Java program How to set path in Java How to check the Java version in cmd How to install Java in Windows 10 How to run Java program in cmd How to add double quotes in a string in Java How to convert list to String in Java How to call a method in Java How to Set Environment Variables for Java How to sort an array in Java How to Create Immutable Classes in Java How to iterate HashMap in Java How to write Java program How to create an array in Java How to create a package in Java How to generate random numbers in Java How to input String in Java How to Create Singleton Class in Java How to sort a string in Java How to use scanner in Java How to achieve multiple inheritance in Java How to find the length of an Array in Java How to Read Java JSON file How to run Java program in Eclipse How to call a function in Java How to create array of objects in Java How to import packages in Java How to run applet Program in Java How to take Array Input in Java How to call static method in Java How to compare characters in Java How to compare dates in Java How to create a linked list in Java How to download Eclipse for Java How to get ASCII value of char in Java How to get the current date and time in Java How to handle NullPointerException in Java How to initialize string array in Java How to Install Java on MAC How to run java program in ubuntu How to find characters with the maximum number of times in a string java How to Set Java_home in Linux How to Split the String in Java with Delimiter How to take Multiple String Input in Java using Scanner class How to uninstall the Java in Ubuntu How to Update Java How to add Elements in Array in Java How to avoid deadlock in java How to Split String by Comma in Java How to remove special characters from String in Java How to remove last character from String in Java How to Read XML Files in Java How to download and install Eclipse in Windows How to Create an API in Java How to Round Double Float up to Two Decimal Places in Java How to create a mirror image of a 2D array in Java How to set timer in Java How to make Java Projects How to Create Different Packages for Different Classes in Java How to run Java program in command prompt How to run Java program in Eclipse How to calculate time difference in Java How to stop execution after a certain time in Java How to check data type in Java How to Reduce Time Complexity in Java How to check if date is valid in Java How many ways to create object in Java How to add 4 Hours to the Current Date in Java How to add 4 Years to the Current Date in Java How to add 6 Months to the Current Date in Java How to add 24 Hours to Date in Java How to Assign Static Value to Date in Java How to check Date is Greater in Java How to check Date Null in Java How to check valid date in Java How to Iterate List in Java How to increment and decrement date using Java How to Create a Generic List in Java How to compare two dates in different format in Java How to compare three dates in Java How to override toString() method in Java

Java 8 Features

Java 8 Features Lambda Expressions in Java Functional Interface in Java Streams in Java Java Base64 Encoding and Decoding Type Annotations in Java Java Stringjoiner Class Parallel Arrays Sort in Java Bifunction in java 8 Java 8 filters list Java 8 Consumer Interface in Java

Java 9 Features

Java 9 Tutorial Java 9 Try With Resources Java 9 Interface Private Method

Java 12

What’s new in Java 12

Java 13

Java 13 New Features

Java 14

New Features of Java 14

Java 15

What’s New in Java 15

Java 16

Java 16

Java 17

What is new in Java 17

Java Math Methods

Math.abs() Math.acos() Math.addExact() Math.asin() Math.atan () Math.atan2() Math.cbrt() Math.ceil() Math.copysign() Math.cos() Math.cosh() Math.decrementExact() Math.exp() Math.expm1() Math.floor() Math.floorDiv() Math.floorMod() Math.fma() Math.getExponent() Math.hypot() Math.IEEEremainder() Math.incrementExact() Math.log() Math.log10() Math.log1p() Math.max() Math.min() Math.multiplyExact() Math.multiplyFull() Math.negateExact() Math.nextAfter() Math.nextDown() Math.nextUp() Math.pow() Math.random() Math.rint() Math.round() Math.scalb() Math.signum() Math.sin() Math.sinh() Math.sqrt() Math.subtractExact() Math.tan() Math.tanh() Math.toDegrees() Math.toIntExact() Math.toRadians() Math.ulp()

Java String Methods

toCharArray() copyValueOf() endsWith() equals() equalsIgnoreCase() format() getBytes() getChars() hashCode() indexOf() intern() isEmpty() join() lastIndexOf() length() replace() replaceAll() replaceFirst() split() startsWith() subSequence() substring() toLowerCase() toUpperCase() trim() valueOf()

Java Conversion

Java Convert String to int Java Convert int to String Java Convert String to long Java Convert long to String Java Convert String to float Java Convert float to String Java Convert String to double Java Convert double to String Java Convert String to Date Java Convert Date to String Java Convert String to Object Java Convert Object to String Java Convert String to char Java Convert char to String Java Convert int to long Java Convert long to int

Java Keywords

Reserved Keywords in Java Java Case Keyword Java Class Keyword Java Continue Keyword Java Default Keyword Java Double Keyword Java Else Keyword Java Enum Keyword Java Extends keyword Java Finally Keyword Java Char Keyword Contextual keywords in Java Java Break Keyword Volatile keyword in Java Java Boolean Keyword Java Byte Keyword The final Keyword in Java Java For Keyword Java Float Keyword Java Instanceof Keyword Java If Keyword Java Int Keyword Java Import Keyword Java Package Keyword Java Public Keyword Java Implements Keyword Java Private keyword Java Protected Keyword Java Short Keyword Java Long Keyword Java Interface Keyword Java Try Keyword Java New Keyword Java Return Keyword Java Null Keyword this keyword in Java

Java Questions

What are Array strings in Java What is String in Java? What is string in Java why it's immutable What is advance Java? What is interpreter in Java? What is anagram in Java? How Many Ways to Create Objects in Java How annotations work in Java What is Core Java Why to use Enum in Java


List all files in a Directory in Java Nonagonal number in Java Null Pointer Exception in Java Package naming convention in Java PriorityBlockingQueue Class in Java Race Condition in Java Repdigit Numbers in Java Rotate matrix by 90 degrees in Java Segment Tree in Java Sierpinski Number in Java Sort Dates in Java Thread Safety and How to Achieve it in Java Normal and Trace of a Matrix in Java Transient variable in Java Tribonacci series in Java Web Crawler in Java Zigzag Traversal of Binary Tree in Java Java Full Stack Java IO filenotfoundexception Java Output Formatting Java Plot Java Pop Java Set to List Java Switch string Java Thread Lifecycle: States and Stages Java Viva Questions and Answers Lazy Propagation in Segment Tree in Java Level order Traversal of a Binary Tree in Java Method chaining in Java Narcissistic Number in Java Java Try-Catch Block Java concurrency interview questions Java CountDownLatch Java Editors Java Font Example of Static import in Java Implementing Queue 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Java Boyer Moore

A string searching or matching technique called the Boyer-Moore algorithm was created in 1977 by Robert S. Boyer and J. Strother Moore. It is the most popular and effective string-matching algorithm. Compared to the brute-force algorithm, it is substantially faster. The Boyer-Moore algorithm, its features, and its application in a Java program will all be covered in this article. It has a temporal complexity of O(nm+s). In most applications, the Boyer-Moore algorithm is the most efficient string-matching algorithm. In text editors, the «search» and «substitute» commands frequently use a simplified version of the algorithm or the entire algorithm.

Worst-case scenario



The above sequence can be found in images and DNA sequences.

Characteristics of the Boyer Moore Algorithm

  • From right to left, it compares each character;
  • O(m+) time and space complexity characterize the pre-processing stage.
  • The searching step has an O(mn) complexity.
  • In the worst scenario, it compares 3n text characters when looking for a non-periodic pattern.
  • The complexity with the best performance is O(n/m).

The algorithm is based on the two heuristics listed below:

  • Character-Jump Heuristics
  • Looking-Glass Heuristics

Let's examine how the Boyer-Moore algorithm works.

The Boyer-Moore algorithm's operation

The method begins tracing characters from the pattern's rightmost character and advances leftward. It employs two pre-computed functions that shift the characters to the right and left, respectively, in the event of any mismatch and complete pattern matching. The good-suffix shift (also known as the matching shift) and the bad-character shift (or occurrence shift) are the names of these two pre-computed shift functions.

Note: Characters should be compared in a right-to-left sequence and aligned left to right to match the pattern.

Bad Character Shift

Skip alignment when there is a mismatch up until one of the following situations does not exist:

  1. Mismatch turns into a match
  2. P avoids mismatching characters

Take the text (T) and pattern (P) shown below as examples.

Boyer Moore Java

Start comparing the pattern now.

Step 1: First, align characters from left to right and compare them from right to left.

We can see that the last three characters of P correspond to those in T. T, the fourth character, is mismatched. As per the above guideline, skip alignment until a mismatch becomes a match. The seventh character (C) in P matched with C in T.

Boyer Moore Java

The above-displayed image shows the partial match.

Step 2: Move three characters to the right to match the pattern.

Compare the characters once more, this time from right to left, after moving. It matches the first character. We see that the character A is absent from the position to the left of P. P then shifts to the past mismatch character (A) in T in this instance.

Boyer Moore Java

The above-displayed image shows the procedure through which P and T attain matches.

Step 3: If P is moved past the mismatched character, we get,

Boyer Moore Java

From the above-displayed image, the pattern is matched. The sequence “CCTTTTGC” matches in both the T and P.

Note: The bad-character shift may not be good. Given that the Boyer-Moore method applies the maximum (skip characters) between the good-suffix shift and bad-character shift, it is appropriate to shift characters in this manner.

Good-Suffix Shift

Let's say that an inner loop matches the substring t. If so, skip characters up until:

  1. No mismatches exist between P and t.
  2. P moves past t.

Consider the following pattern as an example.

Boyer Moore Java

Step 1: Go from right to left and compare the characters. We can see that the last three characters of P correspond to characters in T denoted by t.

Boyer Moore Java

The above-displayed image shows the partial match.

Step 2: Continue until there is no match between P and t. The first four characters (from left to right) of P (C T T A C) correspond to the last five characters in t.

Boyer Moore Java

The above-displayed image shows the procedure through which P and t attain no matches.

Step 3: To get the match, skip three alignments. As a result, we get the match.

Boyer Moore Java

The above-displayed image shows the match. The sequence “CTTACTTAC” matches in both the T and P.

The two-shift functions described above can be defined as follows:

The good-suffix shift function is stored in a table of size m+1 called “bmGs”. The table “bmGs” is computed using a table “suff” defined as follows:

for 1 ? i < m, suff[i]=max{k : x[i-k+1 .. i]=x[m-k .. m-1]} 

The bad-character shift function is stored in a table bmBc of size s. For c in ∑:

bmBc[c] = min{i : 1 ? i <m-1 and x[m-1-i]=c} if c occurs in x, m otherwise. 

Pattern Matching Example Using Boyer Moore

Think about the following pattern.

Boyer Moore Java

Let's begin matching.

Step 1: Characters should be compared from right to left. The first character is mismatched, as G does not match with T.

Boyer Moore Java

Step 2: Skip the following few characters until we find a match. After six characters, a match is made. The good suffix shift rule will not be applicable in this case.

Boyer Moore Java

P moves past mismatch character (i.e. G), according to bad character shift.

Boyer Moore Java

Step 3: Compare characters once more from right to left. We can observe that P's first three characters match (t) with T, but its fourth character does not.

Boyer Moore Java

Both the bad and good character suffix can be used in this situation. When the bad character suffix is used, only one character is skipped. The good character suffix ignores two alignments when used. Therefore, since the algorithm says to skip additional alignments, we will use the good character suffix. Consequently, we omit two alignments.

Boyer Moore Java

Three characters of alignment are changed, and the result is:

Boyer Moore Java

Here, we can see that C is missing from P's area to the left. Good character alignments skip seven alignments, while bad character alignments skip two alignments.

Step 4: We can observe that the string is matched after changing a few characters.

Boyer Moore Java

We skipped 15 alignments in the earlier pattern, and 11 T characters were ignored.

Boyer Moore Pre-processing Phases

The following definition applies to calculated skips for the patterns T: A A T C A A T A G C and P: T C G C. The bad character shift function was employed in the above pattern.

Boyer Moore Java

The above table (characters) shows the number of skip alignments.

Pseudo Code for the Boyer Moore Algorithm

BoyerMooreMatch(H, T, ?)  
K<- lastOccurenceFunction(T, ?)  
i <- m-1  
j <- m-1  
                    if H[i]=T[j]  
                             if j=0  
                                  return i {match at i}  
                                  i <- i-1  
                                  j <- j-1  
                         i <- i +m -min(j, 1+ l)  
                         j <- m-1  
until i>n-1  
return-1 {no match}  

Java Program for Pattern Searching

Let's look at the pattern-finding Java program. The brute-force string searching algorithm is implemented in the following program.

File name:

import java.util.HashMap;  
import java.util.Map;  
public class PatternSearchingExample  
* @example text -- trace the text to see if it contains pattern 
* @example pattern -- look for this text inside the text parameter 
* @return -- return index of the first match or -1 if not found 
public static int findBruteForce(char[] text, char[] pattern)   
System.out.println("Brute force looking for " + String.valueOf(pattern) + " in " + String.valueOf(text)) ;  
int n = text.length ;  
int m = pattern.length ;  
//checks if the string is empty  
if (m == 0) return 0 ;  
//brute force it -- loop over all characters in text O(n)  
for (int i=0;i<=n-m;i++)   
{ //index into the text  
//loop over all characters in pattern while characters match O(m)  
//index into the pattern  
int k = 0 ;   
while (k<m && text[i+k] == pattern[k])   
k++ ;  
//if at the end of the pattern, then found match starting at index i in text  
if (k==m)   
System.out.println("\tFound match in the given text at index " + i) ;  
return i ;  
//if a match is not found  
System.out.println("\tNo match found in the given text.") ;  
return -1 ;  
* @example text -- search this text to see if it contains pattern 
* @example pattern -- look for this text inside the text parameter 
* @return -- return index of the first match or -1 if not found 
public static int findBoyerMoore(char[] text, char[] pattern)   
System.out.println("Boyer-Moore looking for " + String.valueOf(pattern) + " in " + String.valueOf(text)) ;  //valueOf method is used
int n = text.length ;  // n stores length of the text
int m = pattern.length ;  
// Test for empty string  
if (m == 0) return 0 ;  
// Initialization, create Map of last position of each character = O(n)  
Map<Character, Integer> last = new HashMap<>() ;  //Map
for (int i = 0; i < n; i++)   
// set all chars, by default, to -1      
last.put(text[i], -1) ;     
for (int i = 0; i < m; i++)   
// update last seen positions      
last.put(pattern[i], i) ;   
//Start with the end of the pattern aligned at index m-1 in the text.   
//index into the text  
int i = m - 1 ;    
// index into the pattern  
int k = m - 1 ;    
while (i < n)   
if (text[i] == pattern[k])   
// match! return i if complete match; otherwise, keep checking      
if (k == 0)   
System.out.println("\tFound match in the given text at index " + i) ;  
return i ;   
i = i - 1 ; 
{ // jump step + restart at end of pattern  
//iterate over the text   
i += m - Math.min(k, 1 + last.get(text[i])) ;    
//move to the end of the pattern  
k = m - 1 ;   
System.out.println("\tNo match found in the given text.") ;  
// prints as not found  
return -1 ;   
public static void main(String args[])   
char[] text = "abcfefabddef".toCharArray() ;  //string to character array
char[] pattern = "abddef".toCharArray() ;  //string to character array
//function calling  
findBruteForce(text,pattern) ;  //calls the findBruteForce function
findBoyerMoore(text,pattern) ;          //calls the findBruteForce function


Boyer Moore Java

The above-displayed image is the output for the above program, and The output says that "abddef” is present in the “abcfefabddef” at index 6.

Let's use a Java program to implement the algorithm.

The Boyer Moore Java Program

Let's use a Java program to implement the Boyer-Moore algorithm and search pattern.

Program 1


public class BoyerMooreImplementation  
static int NO_OF_CHARS = 256;   
static int max (int a, int b)   
return (a > b)? a: b;   
static void badCharHeuristic( char []str, int size, int badchar[])   
int i;   
for (i = 0; i < NO_OF_CHARS; i++)   
badchar[i] = -1;   
for (i = 0; i < size; i++)   
badchar[(int) str[i]] = i;   
static void search( char txt[],  char pat[])   
int m = pat.length;   
int n = txt.length;   
int badchar[] = new int[NO_OF_CHARS];   
//function calling  
badCharHeuristic(pat, m, badchar);   
int s = 0;    
while(s <= (n - m))   
int j = m-1;   
while(j >= 0 && pat[j] == txt[s+j])   
if (j < 0)   
System.out.println("Patterns occur at character = " + s);   
s += (s+m < n)? m-badchar[txt[s+m]] : 1;   
s += max(1, j - badchar[txt[s+j]]);   
public static void main(String args[])   
//text in which pattern occurs  
char txt[] = "123651266512".toCharArray();   
//pattern to search  
char pat[] = "12".toCharArray();   
search(txt, pat);   


Boyer Moore Java

Let's look at another Java program where we have distinct logic for pattern finding implemented. The code that follows next determines whether the text contains the required pattern.

Program 2


public class BoyerMooreExample  
public static void main(String args[])   
        System.out.println("Matching Pattern");  
        test("aabbccdef", "cde", 0);  
        test("zzzzaaapppxyzabc", "pqrs", 1);  
        test("mango", "ngo", 2);  
        test("abc", "d", -1);  
        test("catdog", "tdo", 2);  
        test("pqrsabcdxyzamnop", "cdxyza", 1);  
        test("cool", "", 0);  
        test("", "car", -1);  
    public static void test(String text, String word, int exp)   
        char[] textC = text.toCharArray();  
        char[] wordC = word.toCharArray();  
        int result = bm(textC, wordC);  
        if(result == exp)  
            System.out.println("Pattern Matched");  
            System.out.println("Pattern Not Matched");  
            System.out.println("\ttext: " + text);  
            System.out.println("\tword: " + word);  
            System.out.println("\texp: " + exp + ", res: " + result);  
        }//end of else  
    }//end of function  
    public static int[] makeD1(char[] pat)   
        int[] table = new int[255];  
        for(int i=0; i<255; i++)  
            table[i] = pat.length;  
        for(int i=0; i<pat.length-1; i++)  
            table[pat[i]] = pat.length-1-i;  
        return table;  
    }//end of the function  
    public static boolean isPrefix(char[] word, int pos)   
        int suffixlen = word.length - pos;  
        for(int i=0; i<suffixlen; i++)  
            if(word[i] != word[pos+i])  
                return false;  
        return true;  
    }//end of the function  
    public static int suffix_length(char[] word, int pos)   
        int i;  
        for(i=0; ((word[pos-i] == word[word.length-1-i]) & (i < pos)); i++)  
            }//end of for loop  
        return i;  
    }//end of the function   
    public static int[] makeD2(char[] pat)   
        int[] delta2 = new int[pat.length];  
        int p;  
        int last_prefix_index = pat.length - 1;  
        for(p = pat.length-1; p>=0; p--)   
            if(isPrefix(pat, p+1))  
                last_prefix_index = p+1;  
            delta2[p] = last_prefix_index + (pat.length-1-p);  
        }//end of for loop  
        for(p=0; p<pat.length-1; p++)   
            int slen = suffix_length(pat, p);  
            if(pat[p-slen] != pat[pat.length-1-slen])  
                delta2[pat.length-1-slen] = pat.length-1-p+slen;  
        }//end of for loop  
        return delta2;  
    }//end of function  
    public static int bm(char[] string, char[] pat)   
        int[] d1 = makeD1(pat);  
        int[] d2 = makeD2(pat);  
        int i = pat.length-1;  
        while(i < string.length)   
            int j = pat.length-1;  
            while(j>=0 && (string[i] == pat[j]))   
                i--; //decrement i by 1  
                j--; //decrement j by 1  
            }//end of while  
            if(j < 0)  
                return (i+1);  
            i += Math.max(d1[string[i]], d2[j]);  
        } //end of while  
        return -1;  
    }//end of the function  


Boyer Moore Java