diff --git a/1-array/java/common_elements.java b/1-array/java/common_elements.java
new file mode 100644
index 0000000..b8dd10b
--- /dev/null
+++ b/1-array/java/common_elements.java
@@ -0,0 +1,43 @@
+package algorithmica;
+
+import java.util.Arrays;
+import java.util.Scanner;
+public class common_elements {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		int [] a,b;
+		int size;
+		Scanner in=new Scanner(System.in);
+		size=in.nextInt();
+		a=new int[size];
+		b=new int[size];
+		for(int i=0;i<a.length;i++)
+			a[i]=in.nextInt();
+		for(int i=0;i<b.length;i++)
+			b[i]=in.nextInt();
+		System.out.println(findCommonElements(a, b));
+	}
+public static int findCommonElements(int[] a,int[] b)
+{
+	Arrays.sort(a);
+	Arrays.sort(b);
+	int i=0,j=0;
+	int count=0;
+	while(i<a.length&&j<b.length)
+	{
+		if(a[i]==b[j])
+		{
+			count++;
+			i++;
+			j++;
+		}
+		else if(a[i]<b[j])
+			i++;
+		else
+			j++;
+	}	
+	return count;
+	
+}
+}
diff --git a/1-array/java/duplicate_integer.java b/1-array/java/duplicate_integer.java
new file mode 100644
index 0000000..68f7869
--- /dev/null
+++ b/1-array/java/duplicate_integer.java
@@ -0,0 +1,27 @@
+package algorithmica;
+import java.util.Scanner;
+public class duplicate_integer {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		Scanner in=new Scanner(System.in);
+		int size=in.nextInt();
+		int[] arr=new int[size];
+		for(int i=0;i<arr.length;i++)
+			arr[i]=in.nextInt();
+
+		System.out.println(findDuplicateElement(arr));
+	}
+	public static int findDuplicateElement(int[] a)
+	{
+		for(int i=0;i<a.length;i++)
+		{
+			if(a[Math.abs(a[i])]<0)
+				return Math.abs(a[i]);
+			else
+				a[Math.abs(a[i])]*=-1;
+		}
+		return -1;
+	}
+
+}
diff --git a/1-array/java/majority.java b/1-array/java/majority.java
new file mode 100644
index 0000000..bf8d7eb
--- /dev/null
+++ b/1-array/java/majority.java
@@ -0,0 +1,40 @@
+package algorithmica;
+import java.util.*;
+
+public class majority {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		Scanner in=new Scanner(System.in);
+		int size=in.nextInt();
+		int[] arr;
+		arr=new int[size];
+		for(int i=0;i<arr.length;i++)
+			arr[i]=in.nextInt();
+		Arrays.sort(arr);
+		int prev=arr[0],count=1,maxcount=1,popular=arr[0];
+		for(int i=1;i<arr.length;i++)
+		{
+			if(arr[i]==prev)
+			{
+				count++;
+			}
+			else
+			{
+				if(count>maxcount)
+				{
+					maxcount=count;
+					popular=arr[i-1];
+				}
+				count=1;
+				prev=arr[i];
+			}	
+		}
+		popular=count>maxcount?arr[arr.length-1] : popular;
+		count=(count>maxcount)?count:maxcount;
+		System.out.println(popular+" "+count);
+		
+		
+	}
+
+}
diff --git a/1-array/java/search2dArray.java b/1-array/java/search2dArray.java
new file mode 100644
index 0000000..444e15a
--- /dev/null
+++ b/1-array/java/search2dArray.java
@@ -0,0 +1,53 @@
+package algorithmica;
+import java.util.Scanner;
+public class search2dArray {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		int size;
+		Scanner in=new Scanner(System.in);
+		size=in.nextInt();
+		int [][] arr=new int[size][size];
+		for(int i=0;i<arr.length;i++)
+			for(int j=0;j<arr.length;j++)
+				arr[i][j]=in.nextInt();
+		int x=in.nextInt();
+		pair p=findElementIndex(arr, x);
+		p.getindex();
+	
+	}
+	public static pair findElementIndex(int[][] a,int x)
+	{
+		int ri=0;
+		int ci=a.length-1;
+		while(ri<a.length&&ci>=0)
+		{	
+			if(a[ri][ci]==x)
+				return new pair(ri,ci);
+			else if(x>a[ri][ci])
+				ri++;
+			else
+				ci--;
+		}
+		return new pair(-1,-1);
+		
+	
+	}
+
+}
+
+
+class pair
+{
+	private int ri;
+	private int ci;
+	public pair(int ri,int ci)
+	{
+		this.ri=ri;
+		this.ci=ci;
+	}
+	public void getindex()
+	{
+		System.out.println(this.ri+" "+this.ci);
+	}
+}
\ No newline at end of file
diff --git a/1-array/java/trailingzeroes.java b/1-array/java/trailingzeroes.java
new file mode 100644
index 0000000..281d378
--- /dev/null
+++ b/1-array/java/trailingzeroes.java
@@ -0,0 +1,46 @@
+package algorithmica;
+
+import java.util.Scanner;
+
+public class trailingzeroes {
+
+	public static void main(String[] args) {
+		// TODO Auto-generated method stub
+		Scanner in=new Scanner(System.in);
+		int size=in.nextInt();
+		int[] arr=new int[size];
+		for(int i=0;i<arr.length;i++)
+			arr[i]=in.nextInt();
+		System.out.println(findtralingzeroes(arr));
+
+	}
+
+	private static int findtralingzeroes(int[] a) {
+		// TODO Auto-generated method stub
+		int low=0;
+		int high=a.length-1;
+		int mid;
+		while(low<high-1)
+		{
+			mid=(high+low)/2;
+			if(a[mid]==0)
+			{
+				low=mid;
+			}
+			else
+			{
+				high=mid-1;
+			}
+			
+		}
+		if(a[high]==0)
+			return high+1;
+		if(a[low]==0)
+			return low+1;
+		
+		
+		
+		return 0;
+	}
+
+}
diff --git a/3-set/java/paragraph.java b/3-set/java/paragraph.java
new file mode 100644
index 0000000..4c61011
--- /dev/null
+++ b/3-set/java/paragraph.java
@@ -0,0 +1,53 @@
+package algorithmica;
+
+import java.io.BufferedReader;
+import java.io.FileNotFoundException;
+import java.io.FileReader;
+import java.io.IOException;
+import java.util.HashMap;
+
+public class paragraph {
+
+	public static void main(String[] args) throws IOException {
+		// TODO Auto-generated method stub
+		String mystring;
+		String[] line;
+		int i=1,value,count=0,maxcount=0,linenumber=0;
+		HashMap<String, Integer> map=new HashMap<String, Integer>();
+		BufferedReader br=new BufferedReader(new FileReader("C:\\Users\\rohith\\algoritmica\\algorithmica\\src\\testcases\\paragraph.txt"));
+		while((mystring=br.readLine())!=null)
+		{
+			count=0;
+			
+			line=mystring.split(" ");
+			for(String s:line)
+			{
+				//check whether list is empty
+				
+				if(map.containsKey(s))
+				{
+					value=map.get(s);
+					if(value<i)
+					{
+						map.remove(s);
+						map.put(s,i);
+						count++;
+					}
+				}
+				else
+				{
+					map.put(s, i);
+					count++;
+				}
+			}
+			if(count>maxcount)
+			{
+				maxcount=count;
+				linenumber=i;
+			}
+			i++;
+		}
+		System.out.print(maxcount+" "+linenumber+" "+map.size());
+	}
+
+}
diff --git a/3-set/java/paragraph.txt b/3-set/java/paragraph.txt
new file mode 100644
index 0000000..f39906a
--- /dev/null
+++ b/3-set/java/paragraph.txt
@@ -0,0 +1,5 @@
+hello i am rohith
+this is again rohith rohith
+this is again rohith hello i am
+this is again
+this is again rohith hello i am while i am king
\ No newline at end of file