ADDITIONAL SYSTEM INFORMATION :
Ubuntu 18.04.6 LTS

A DESCRIPTION OF THE PROBLEM :
When I run the Test.java file using hotspot-jdk-21.0.2, there are illegal strings in the java file and three errors occurred in hotspot-jdk-21.0.2. Immediately after I used hotspot-jdk-11.0.15 and hotspot-jdk8u352 to run the file, four errors occurred. I think four mistakes are more reasonable.

STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
cmd:hotspot-jdk-21.0.2/build/linux-x86_64-server-fastdebug/jdk/bin/javac Test.java

EXPECTED VERSUS ACTUAL BEHAVIOR :
EXPECTED -
Expected Result:
[FOLDER]/openjdk/hotspot-jdk-11.0.15/build/linux-x86_64-normal-server-fastdebug/jdk/bin/java Test.java
Test.java:5: error: illegal escape character
    static String fParam1Param1Param1 = "i+eq.$s\ "Pt";
                                                 ^
Test.java:5: error: ';' expected
    static String fParam1Param1Param1 = "i+eq.$s\ "Pt";
                                                   ^
Test.java:5: error: unclosed string literal
    static String fParam1Param1Param1 = "i+eq.$s\ "Pt";
                                                     ^
Test.java:33: error: class, interface, or enum expected
}
^
4 errors
error: compilation failed
ACTUAL -
[FOLDER]/openjdk/hotspot-jdk-21.0.2/build/linux-x86_64-server-fastdebug/jdk/bin/javac Test.java
Test.java:5: error: illegal escape character
    static String fParam1Param1Param1 = "i+eq.$s\ "Pt";
                                                 ^
Test.java:5: error: unclosed string literal
    static String fParam1Param1Param1 = "i+eq.$s\ "Pt";
                                                     ^
Test.java:33: error: class, interface, enum, or record expected
}
^
3 errors

---------- BEGIN SOURCE ----------
import java.io.*;

public class Test {
    static String fParam1Param1Param1 = "i+eq.$s\ "Pt";
    static File fParam1Param1 = new File(fParam1Param1Param1);
    static String fParam1Param2 = ",q<f:|06Gz";
    static File fParam1 = new File(fParam1Param1, fParam1Param2);
    static String fParam2 = "_=+dS!{./C";
    static File f = new File(fParam1, fParam2);

    String read(File f) throws IOException {
        int enda = 0;
        int starta = 5;
        StringBuilder sb = new StringBuilder();
        BufferedReader in = new BufferedReader(new FileReader(f));
        try {
            String line;
            while ((line = in.readLine()) != null) {
                sb.append(line);
                sb.delete(starta, enda);
            }
        } finally {
            in.close();
        }
        return sb.toString();
    }

    public static void main(String[] args) throws Exception {
        System.out.println(new Test().read(f));
    }
}
---------- END SOURCE ----------