Resolving java.lang.IllegalArgumentException: Illegal Base64 Character 9

Have you encountered the java.lang.IllegalArgumentException error with an illegal base64 character 9? This guide will help you understand the reasons behind this error and provide effective solutions to fix it and ensure the proper encoding and decoding of base64 strings in Java.

Understanding java.lang.IllegalArgumentException

java.lang.IllegalArgumentException is an exception in Java that occurs when a method receives an argument that is not valid for its intended use. In this case, the error is caused by an illegal base64 character (9) during the encoding or decoding process.

Causes of java.lang.IllegalArgumentException: Illegal Base64 Character 9

This error can arise due to the following reasons:

Resolving the Issue

1. Validate the Base64 Input String

Ensure that the input string provided for encoding or decoding is a valid base64 string. Base64 strings should only contain characters from the standard base64 alphabet (A-Z, a-z, 0-9, +, and /) and may be padded with one or two ‘=’ characters at the end. Check your input string for any illegal characters or formatting issues and correct them as needed.

2. Use the Correct Encoding and Decoding Method

Verify that you are using the proper method for encoding and decoding base64 strings in Java. The java.util.Base64 class provides methods for encoding and decoding, such as getEncoder() and getDecoder(). Make sure to use the appropriate method for your specific use case.

// Encoding a byte array to a base64 string
Base64.Encoder encoder = Base64.getEncoder();
String encodedString = encoder.encodeToString(byteArray);

// Decoding a base64 string to a byte array
Base64.Decoder decoder = Base64.getDecoder();
byte[] decodedByteArray = decoder.decode(encodedString);

Conclusion

By understanding the causes of java.lang.IllegalArgumentException errors related to illegal base64 character 9, you can effectively resolve the issue and ensure the proper encoding and decoding of base64 strings in Java. Remember to validate the input string and use the correct encoding and decoding method for your specific scenario. Happy coding!

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