Two ways to write a binary string

// create a test string
String testString = "This is a test string.\n";

// use the writeUTF method
out.writeUTF(testString);
int writeSize1 = out.size();
System.out.println(
    "writeUTF writes " + writeSize1 + " bytes.");

// use the writeChars method
out.writeChars(testString);
int writeSize2 = out.size() - writeSize1;
System.out.println(
    "writeChars writes " + writeSize2 + " bytes\n");

out.close();

Output of the code that writes a binary string

writeUTF writes 25 bytes.
writeChars writes 46 bytes.

The file opened in a text editor

Two ways to read a binary string

// get total bytes
int totalBytes = in.available();

// use the readUTF method
String string1 = in.readUTF();
int readSize1 = totalBytes - in.available();
System.out.println("readUTF reads " + readSize1 + " bytes.");

// use the readChar method
int readSize2 = 0;
String string2 = "";
for (int i = 0; i < testString.length(); i++)
{
    string2 += in.readChar();
    readSize2 += 2;
}
System.out.println(
    "readChar reads " + readSize2 + " bytes.\n");

Output of the code that reads a binary string

readUTF reads 25 bytes.
readChar reads 46 bytes.