Error in java

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package codechef; // don’t place package name! */

import java.util.;
import java.lang.
;
import java.io.*;

/* Name of the class has to be “Main” only if the class is public. /
public class Codechef
{
public static void main (String[] args) throws java.lang.Exception
{
// your code goes here
/
package codechef; // don’t place package name! */

/* Name of the class has to be “Main” only if the class is public. */
Scanner scan = new Scanner(System.in);
int t = scan.nextInt();
while(t–>0)
{
int n = scan.nextInt();
int a[] = new int[n];
int result = 0;
for(int i=0;i<n;i++)
{
result = Fib(i);
a[i] = result%10;
}
int ans = find_one(a);
System.out.println(ans);
}
}
public static int Fib(int n)
{
if(n==0)
return 0;
else if(n==1)
return 1;
else
return (Fib(n-1)+Fib(n-2));
}
public static int find_one(int a[])
{
int b[] = new int[a.length/2];
int j=0;
for(int i=0;i<a.length;i++)
{
if(i%2==1)
{
b[j]=a[i];
j++;
}
}
if(b.length != 1)
return find_one(b);
else
return b[0];

    }
}

ERROR IS:

Main.java:15: error: class Codechef is public, should be declared in a file named Codechef.java
public class Codechef
^
1 error

The name of the class that contains the main() method should be filename.
In your case, the filename seems to be Main.java, so your class should be: public class Main{…

I did that but it’s showing illegal start of expression.
the same code is running perfectly in onlinegdb.com compiler

Since the class is public and the name given for class is Codechef , the file should be saved with class name when the class is public , the file name should be Codechef.java

Yes but is there any provision to change file name because these file are by default