Added Linear Search in Java

Searching/LinearSearch.java

@@ -0,0 +1,51 @@
+/**
+ * Algorithm : Linear Search
+ * Description: Given an array of integers and you need to find a key or a number. If you finds the key in the array, it returns TRUE otherwise FALSE
+ * Time Complexity : O(n)
+ */
+
+import java.util.*;
+
+public class LinearSearch {
+    private static final String ERROR_STRING = "Please provide a list of integers (\"1, 4, 5, 11, 12\") and the integer to find (\"11\")";
+    public static void main(String[] args) {
+        try {
+            // Returns TRUE
+            List<Integer> listOfNumbers = new ArrayList<Integer>(Arrays.asList(1,2,3,4,5));
+            Integer keyToSearch = 5;
+            InputOutputMethod(listOfNumbers, keyToSearch);
+
+            // Returns FALSE
+            keyToSearch = 6;
+            InputOutputMethod(listOfNumbers, keyToSearch);
+
+            // Gives error as no input
+            listOfNumbers = new ArrayList<Integer>(Arrays.asList());
+            InputOutputMethod(listOfNumbers, keyToSearch);
+        }
+        catch(Exception e) {
+            System.out.println(ERROR_STRING);
+        }
+    }
+
+    private static void InputOutputMethod(List<Integer> listOfNumbers, Integer keyToSearch) {
+        if(listOfNumbers.size() >= 1){
+            StringBuilder output = new StringBuilder();
+            Boolean searched = linearSearch(listOfNumbers, keyToSearch);
+            System.out.println(searched);
+        }else{
+            System.out.println(ERROR_STRING);
+        }
+    }
+
+    private static Boolean linearSearch(List<Integer> list, Integer keyToSearch) {
+        Boolean answer = false;
+        for (Integer number : list) {
+            if(number == keyToSearch) {
+                answer = true;
+                break;
+            }
+        }
+        return answer;
+    }
+}