*****HELP WITH JAVA! Im completelt lost on this Assignment.... Please show OUTPUT and Explain on what i need to do in order to use the program!! Thanks

Try to find two words with the same hash code in a large file. Keep a Map.When you read in a word, compute its hash code h and put the word in the set whose key is h. Then iterate through all keys and print the sets whose size is > 1

import java.io.FileNotFoundException; import java.io.IOException; import java.util.Collection; import java.util.Map; import java.util.Scanner; import java.util.Set; import java.util.TreeMap; public class AirportTester { public static void main( String[] args ) { Collection airportData = loadAirportData( "us_airports.csv"); displayAirportData(airportData); AirportTable airportTable = buildAirportTable( airportData ); Scanner inp = new Scanner( System.in ); System.out.print("command> "); while( inp.hasNextLine()) { String line = inp.nextLine(); if(line == null || line.isEmpty()) { continue; } String[] param = line.split(" "); if( param.length <= 1 ) { continue; } String command = param[0].toLowerCase(); if("findbycode".equals(command)) { findByCode( airportTable, param[1] ); } else if("findbystate".equals(command)) { findByState( airportTable, param[1] ); } else if("findbyname".equals(command)) { findByName( airportTable, param[1] ); } else if("findbycity".equals(command)) { findByCity( airportTable, param[1], param[2]); } else if( "countbystate".equals(command)) { countByState( airportTable, param[1] ); } else if( "quit".equals(command)) { break; } System.out.println(); System.out.print("command> "); } } private static Collection loadAirportData( String filename ) { Collection airportData = null; try { airportData = AirportDataLoader.load(filename); } catch (FileNotFoundException e ) { System.out.println( e.getMessage()); } catch( IOException e ) { System.out.println( e.getMessage()); } return airportData; } private static AirportTable buildAirportTable( Collection airportData ) { AirportTable airportTable = new AirportTable(); for( Airport airport : airportData ) { boolean inserted = airportTable.insert(airport); if( ! inserted ) { System.out.printf( "Insert Failed: %d%n", airport); } } return airportTable; } private static void countByState( AirportTable airportTable, String state) { Collection list = null; if( !"*".equals(state) ) { int count = airportTable.countByState(state); System.out.printf("%d airports%n", count); } else { Set states = airportTable.allStates(); Map stateCounts = new TreeMap(); int total = 0; for( String stateAbbrev : states ) { int count = airportTable.countByState(stateAbbrev); total += count; stateCounts.put(stateAbbrev, count); } int perLineCount = 0; Set sortedStates = stateCounts.keySet(); for( String stateAbbrev : sortedStates ) { System.out.printf(" %s %4d", stateAbbrev, stateCounts.get(stateAbbrev).intValue()); ++ perLineCount; if( perLineCount % 4 == 0) { System.out.println(); perLineCount = 0; } } System.out.println(); } } private static void findByCity( AirportTable airportTable, String city, String state) { Collection list = airportTable.findByCity(city, state); if( list == null ) { System.out.println("No airports found"); } else { displayAirportData( list ); } } private static void findByCode( AirportTable airportTable, String code ) { Airport airport = airportTable.findByCode(code); if( airport == null ) { System.out.println("No airports found"); } else { System.out.println(airport); } } private static void findByName( AirportTable airportTable, String name ) { Collection list = airportTable.findByName(name); if( list == null ) { System.out.println("No airports found"); } else { displayAirportData( list ); } } private static void findByState( AirportTable airportTable, String state) { Collection list = airportTable.findByState(state); if( list == null ) { System.out.println("No airports found"); } else { displayAirportData( list ); } } private static void displayAirportData(Collection airportData) { for( Airport airport : airportData ) { System.out.println(airport); } } } 

AND HERES THE SECOND CODE:

import java.util.ArrayList; import java.util.Collection; import java.util.HashMap; import java.util.LinkedList; import java.util.List; import java.util.Map; import java.util.Set; import java.util.SortedMap; import java.util.TreeMap; public class AirportTable { private Map codeMap; private Map> stateMap; private Map> cityMap; private SortedMap nameMap; public AirportTable() { codeMap = new HashMap(); stateMap = new HashMap>(); cityMap = new HashMap>(); nameMap = new TreeMap(); } public boolean insert( Airport airport ) { if( airport == null ) { return false; } String code = airport.getCode(); String name = airport.getName(); String city = airport.getCity(); String state = airport.getState(); if( code == null || city == null || state == null ) { return false; } if( name == null ) { name = city + " " + state; } code = code .toUpperCase(); name = name.toUpperCase(); city = city.toUpperCase(); state = state.toUpperCase(); codeMap.put(code, airport); List stateList = stateMap.get(state); if( stateList == null ) { // State is not in the table stateList = new LinkedList(); stateMap.put(state, stateList); } stateList.add(airport); CityKey cityKey = new CityKey( city, state ); List cityList = cityMap.get(cityKey); if( cityList == null ) { // State is not in the table cityList = new LinkedList(); cityMap.put(cityKey, cityList); } cityList.add(airport); nameMap.put(name, airport); return true; } public Airport findByCode( String code ) { if( code == null ) { return null; } Airport airport = codeMap.get(code.toUpperCase()); return airport; } public Set allCodes() { Set codes = codeMap.keySet(); return codes; } public Collection findByState( String state ) { if( state == null ) { return null; } Collection retList = null; List list = stateMap.get(state.toUpperCase()); if( list != null ) { retList = new ArrayList(list); } return retList; } public Set allStates() { Set states = stateMap.keySet(); return states; } public int countByState( String state ) { if( state == null ) { return -1; } int count = 0; List list = stateMap.get(state.toUpperCase()); if( list != null ) { count= list.size(); } return count; } public Collection findByCity( String city, String state ) { if( city == null || state == null ) { return null; } Collection retList = null; CityKey cityKey = new CityKey( city.toUpperCase(), state.toUpperCase()); List list = cityMap.get(cityKey); if( list != null ) { retList = new ArrayList(list); } return retList; } // public Set allCities() { // Set states = stateMap.keySet(); // return states; // } public int countByCity( String city, String state ) { if( city == null || state == null ) { return -1; } int count = 0; CityKey cityKey = new CityKey( city.toUpperCase(), state.toUpperCase()); List list = cityMap.get(cityKey); if( list != null ) { count= list.size(); } return count; } public Collection findByName( String name ) { if( name == null ) { return null; } Collection retList = null; String fromNameKey = name.toUpperCase() + Character.MIN_VALUE; String toNameKey = name.toUpperCase() + Character.MAX_VALUE; SortedMap map = nameMap.subMap(fromNameKey, toNameKey); if( map != null ) { retList = map.values(); } return retList; } private class CityKey implements Comparable { private String city; private String state; public CityKey() { this("",""); } public CityKey( String city, String state ) { this.city = city; this.state = state; } public int compareTo( CityKey other ) { int ret = city.compareTo(other.city); if( ret == 0 ) { ret = state.compareTo(other.state); } return ret; } @Override public boolean equals( Object object ) { if( this == object ) { return true; } if( object == null ) { return false; } if(getClass() != object.getClass()) { return false; } CityKey other = (CityKey) object; return compareTo(other) == 0; } @Override public int hashCode() { int hash = 0; if( city != null ) { hash += 7 * city.hashCode(); } if( state != null ) { hash += 11 * state.hashCode(); } return hash; } } }