Java idiom

package test;

import java.io.BufferedWriter;
import java.io.File;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Scanner;

public class test1 {

    public static void main(String[] args) throws IOException {
        File file = new File("D:\\input.txt");
        if (!file.exists()) {
            System.out.println("文件不存在");
            return;
        
        }
        String[] strs=new String[99999999];
        Scanner x = new Scanner(file);
        int i=0;
        boolean flag=false;
        while(x.hasNextLine()) {
            String[] str=x.nextLine().split("\\W+");
            for(int ms=0;ms<str.length;ms++) {
                if(!str[ms].equals("")&&str[ms].length()>2) {
                    flag=false;
                    if(i!=0) {
                        for(int t=0;t<i;t++) {
                            if(!str[ms].equals(strs[t])) {
                                flag=true;
                            }
                        }
                    }else {
                        flag=true;
                    }
                    
                    if(flag) {
                        strs[i]=str[ms];
                        i++;
                    }
                    
                }
                
            }
        }
        
        String sentence = "";
        String word="";
        String max="";
        for(int m=0;m<i;m++) {
            sentence = strs[m];
            word = sentence;
            for(int j=m+1;j<i;j++) {
                if(strs[j].toLowerCase().subSequence(0, 1).equals(word.toLowerCase().subSequence(word.length()-1, word.length()))) {
                    word = strs[j];
                    sentence+="-"+word;
                }
            }
            
            if(sentence.indexOf("-")!=-1) {
                if(sentence.length()>max.length()) {
                    max = sentence;
                }
//                System.out.println(sentence);
            }
            
        }
        File w = new File("D://output.txt"); 
        w.createNewFile(); // 创建新文件
        BufferedWriter out = new BufferedWriter(new FileWriter(w));
        out.write(max); // \r\n即为换行
        out.flush (); // the file buffer contents is pressed into 
        the out.close (); // Finally, remember to close the file 


        
        IF (max.length () = 0! ) { 
            System.out.println (max); 
        } the else { 
            System.out.println ( "no end to end" ); 
        } 
        
    } 
}

Input.txt read the file as the output file to output.txt.