Why isn't BufferedWriter writing into file?

package com.mycompany.mavenproject1;
import java.io.BufferedWriter;
import java.io.IOException;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Paths;
import java.math.BigDecimal;
public class Main {
public BufferedWriter writer;
public Main() {
Charset charset = Charset.forName("US-ASCII");
try {
this.writer = Files.newBufferedWriter(Paths.get("test.txt"), charset);
} catch (IOException e) {
System.err.format("IOException: %s%n", e);
}
}
public void print_fees(String msg, BigDecimal b) {
try {
int msg_len = msg.length();
int t;
t = 34 - msg_len;
t = t - 6;
this.writer.write(msg + String.format("%" + t + "s", b));
this.writer.newLine();
} catch (IOException e) {
System.err.format("IOException: %s%n", e);
}
}
public static void main(String args[]) {
BigDecimal b = new BigDecimal(2);
Main obj = new Main();        
try {
obj.print_fees("Fee: ", b);
} catch (Exception e) {
System.err.format("Exception: %s%n", e);
}
}
}

Why isn't BufferedWriter writing into file?

The point of BufferedWriter is to buffer written content into memory prior to writing it to whatever underlying implementation. When the buffer is filled in memory, it will write in bulk. This generally improves performance of writing, as doing a direct file/disk write for each small write can kill performance due to I/O blocking.

You need to flush the stream explicitly to indicate you want the entire buffer in memory to be written to the underlying implementation (in this case, a file writer) by invoking BufferedWriter#flush() after you have written to the writer. For example,
this.writer.flush().

Also, you should make a habit of closing open OutputStreams/Writers when you are done with them with BufferedWriter#close(). BufferedWriter will automatically invoke BufferedWriter#flush() for you, writing all your writes to whatever the underlying implementation is, without needing to explicitly invoke BufferedWriter#flush(). For example, close your writer once you have finished writing to your Writer: this.writer.close()

this.writer.write(msg + String.format("%" + t + "s", b));
this.writer.flush();