Class JsonException

java.lang.Object
java.lang.Throwable
java.lang.Exception
java.lang.RuntimeException
dev.langchain4j.exception.LangChain4jException
dev.langchain4j.exception.JsonException
All Implemented Interfaces:
Serializable
Direct Known Subclasses:
JsonReadException, JsonWriteException
public class JsonException extends LangChain4jException
Thrown when LangChain4j cannot read or write JSON.

Which JSON library is doing the work is a detail of how the application is assembled, so the exception a caller sees should not depend on it. That library's own failure is kept as the cause.

Not yet reported everywhere. The codecs in langchain4j-jackson3 report failures as these types. The Jackson 2 codecs, which are what LangChain4j uses by default, still wrap Jackson's own exception in a plain RuntimeException as they always have, so that code written against them keeps working. They will move to these types in the next major version; until then, catching RuntimeException is what covers both.

Catch JsonReadException or JsonWriteException to tell the two apart: a read failure means the input was not what was expected, which is often worth retrying or reporting, while a write failure means the object being written cannot be represented, which is a bug.

The document being read is deliberately not part of the message: it is untrusted input that regularly carries credentials or user data, and exception messages end up in logs. What the message does carry is the underlying library's reason for failing, and that reason can quote the fragment it tripped on - the value that would not convert, or the token that would not parse. So the message is bounded, not sanitised.

See Also:

  • Constructor Details

    • JsonException

      public JsonException(String message)

    • JsonException

      public JsonException(String message, Throwable cause)