Slight rehash.

Java/lab_1/lab_1.java

@@ -1,3 +1,5 @@
+package OOP.Java.lab_1;
+
 import java.util.Scanner;
 
 public class lab_1 {

Java/lab_1/lab_1.kt

@@ -1,3 +1,5 @@
+package OOP.Java.lab_1
+
 fun protectedInput(variableName: String): Int {
     do {
         try {

Java/lab_2/lab_2.java

@@ -1,3 +1,5 @@
+package OOP.Java.lab_2;
+
 import java.util.Scanner;
 
 public class lab_2 {
@@ -23,9 +25,8 @@ public class lab_2 {
 
     public static String format(int number) {
         int width = String.valueOf(number).length() + 1;
-        String format = "|%" + width + "d ";
 
-        return format;
+        return "|%" + width + "d ";
     }
 
     public static double average(short[] row) {
@@ -35,18 +36,15 @@ public class lab_2 {
             sum += element;
         }
 
-        double result = sum / row.length;
-
-        return result;
+        return (double) sum / row.length;
     }
 
     public static void main(String[] args) {
-        short a, rows = 0, columns = 0;
-        String format;
+        short rows, columns;
 
         Scanner input = new Scanner(System.in);
 
-        a = protectedInput("Input a constant to multipy a matrix by: ",
+        final short a = protectedInput("Input a constant to multiply a matrix by: ",
                 "A constant must be a short-data type integer, try again.", input);
 
         System.out.println();
@@ -69,7 +67,7 @@ public class lab_2 {
         System.out.println();
         System.out.println("Matrix B:");
 
-        format = format(rows * columns);
+        String format = format(rows * columns);
 
         for (short i = 0; i < rows; i++) {
             for (short j = 0; j < columns; j++) {
@@ -88,7 +86,7 @@ public class lab_2 {
 
         for (short i = 0; i < matrix_B.length; i++) {
             for (short j = 0; j < matrix_B[i].length; j++) {
-                matrix_B[i][j] *= (short) (a);
+                matrix_B[i][j] *= (a);
 
                 System.out.printf(format, matrix_B[i][j]);
             }

Java/lab_3/lab_3.java

@@ -19,7 +19,6 @@ public class lab_3 {
             result = string.substring(leftBoundary + 1, rightBoundary);
             maxStrLength = rightBoundary - leftBoundary - 1;
         }
-        return;
     }
 
     public static int longestPalSubstr(StringBuilder string)
@@ -40,9 +39,9 @@ public class lab_3 {
 
     public static String compareStrings(StringBuilder builder) {
         for (int leftBoundary = 0; leftBoundary <= builder.length(); leftBoundary++) {
-            for (int rightBoundary = builder.length(); leftBoundary >= 0; rightBoundary--) {
-                if (result.equals(builder.substring(leftBoundary, rightBoundary).toString().toLowerCase().replaceAll("[^a-z]",""))) {
-                    return builder.substring(leftBoundary, rightBoundary).toString();
+            for (int rightBoundary = builder.length(); rightBoundary >= leftBoundary; rightBoundary--) {
+                if (result.equals(builder.substring(leftBoundary, rightBoundary).toLowerCase().replaceAll("[^a-z]",""))) {
+                    return builder.substring(leftBoundary, rightBoundary);
                 }
             }
         }
@@ -52,7 +51,7 @@ public class lab_3 {
     public static void main(String[] args) {
         StringBuilder stringToDetect = new StringBuilder("Eva, can I see bees in a cave?");
 
-        System.out.println("Initial string: " + stringToDetect.toString());
+        System.out.println("Initial string: " + stringToDetect);
         System.out.println("Length is: " + longestPalSubstr(stringToDetect));
     }
 }