package lab1;   /** * A utility class containing several recursive methods * * * * For all methods in this API, you are forbidden to use any loops, * String or List based methods such as "contains", or methods that use regular expressions * * * */ public final class Lab1 { /** * This is empty by design, Lab class cannot be instantiated */ privateLab1(){ // empty by design }   /** * Returns the product of a consecutive set of numbers from start * to end . * * @param start is an integer number * @param end is an integer number * @return the product of start * (start + 1) * ..*. + end * @pre. * start and end are small enough to let * this method return an int. This means the return value at most * requires 4 bytes and no overflow would happen. */ publicstaticintproduct(ints,inte){ if(s==e){ returne; }else{ returns*product(s+1,e); } }   publicstaticvoidmain(String[]args){ ints=1; inte=5; intresult=product(s,e); System.out.println("The product is: "+result);     return-999; }   /** * This method creates a string using the given char by repeating the character * n times. * * @param first is the given character by which the string is made. * @param n is the number of characters in the final string * @return a string made of the given character. * * @pre. n is not negative. */ publicstaticStringmakeString(charfirst,intn){ returnnull; charfirst='#'; intn=5; Stringoutput=makeString(first,n); System.out.println(output); }   publicstaticStringmakeString(charch,intn){ if(n<=0){ return""; }else{ returnch+makeString(ch,n-1); } }     /** * This method accepts a positive integer n and that returns n characters: The * middle character should always be an asterisk ("*"). If you are writing an * even number of characters, there will be two asterisks in the middle ("**"). * Before the asterisk(s) you should add less-than characters {@code ("<")}. * After the asterisk(s) you should add greater-than characters {@code (">")}. * * @param n is the total number of strings returned by the method * @return returns a string made of 1 or 2 stars between a number of * {@code ("<")} and {@code (">")} characters. The string length should * be equal to n * @pre. the integer n should be positive */ publicstaticStringwriteChars(intn){ returnnull; System.out.println(writeChars(1));// Output: * System.out.println(writeChars(2));// Output: ** System.out.println(writeChars(3));// Output: <*> System.out.println(writeChars(4));// Output: <**> System.out.println(writeChars(5));// Output: <<*>> System.out.println(writeChars(6));// Output: <<**>> System.out.println(writeChars(7));// Output: <<<*>>> System.out.println(writeChars(8));// Output: <<<**>>> }   publicstaticStringwriteChars(intn){ if(n==1){ return"*"; }elseif(n==2){ return"**"; }else{ return"<"+writeChars(n-2)+">"; } } }   /** * This method returns a substring of the given input string that is enclosed in * two given characters. * * @param str is a string that contains at least two characters including * open and close * @param open is a character at the beginning of the string that should be * returned. * @param close is a character at the end of the string that should be returned. * @return returns a string enclosed in two given characters of * open and close . * @pre. The given str * contains only one open and one close * character. */ publicstaticStringgetSubstring(Stringinput,charfirst,charsecond){ returnnull; Stringinput="Hello (there] how are you?"; charfirst='('; charsecond=']'; Stringoutput=extractEnclosedSubstring(input,first,second); System.out.println(output);// Output: there }   publicstaticStringextractEnclosedSubstring(Stringinput,charfirst,charsecond){ intIndexone=input.indexOf(first); intIndextwo=input.indexOf(second);   if(Indexone!=-1&&Indextwo!=-1&&Indextwo>Indexone){ returninput.substring(Indexone+1,Indextwo); }else{ returnnull;// Enclosing characters not found or in incorrect order } } }       /** * This method converts a decimal value into its binary representation. * * @param value is a positive integer number * @return the binary representation of the input. * @pre. the input is a positive * integer number. */   publicstaticStringdecimalToBinary(intdec){ intdec=23; Stringbinary=decimalToBinary(dec); System.out.println(binary); }   publicstaticStringdecimalToBinary(intn){ if(n==0){ return"0"; }elseif(n==1){ return"1"; }else{ intq=n/2; intr=n%2; returndecimalToBinary(q)+Integer.toString(r); } } }     returnnull; } heres my code in eclipse IDE, can you please fix the errors because it will not run.  }