Java {BSL_LS_MIN_JAVA_VERSION}+ is required for BSL Language

Error message

Java {BSL_LS_MIN_JAVA_VERSION}+ is required for BSL Language Server, but '{java_exe}' is Java {major}. Install a newer JDK (e.g. Temurin {BSL_LS_MIN_JAVA_VERSION}) and ensure it appears first on PATH or point JAVA_HOME to it.

What it means

_verify_java_available raises RuntimeError when java is found on PATH but its detected major version is below BSLS_MIN_JAVA_VERSION. BSL Language Server requires a modern JDK; an old Java cannot run it.

Source

Thrown at src/solidlsp/language_servers/bsl_language_server.py:95


def _verify_java_available() -> None:
    """Ensures a suitable ``java`` (>= :data:`BSL_LS_MIN_JAVA_VERSION`) is on ``PATH``.

    :raises RuntimeError: if ``java`` is missing or its major version is too low.
    """
    java_exe = shutil.which("java")
    if java_exe is None:
        raise RuntimeError(f"Java {BSL_LS_MIN_JAVA_VERSION}+ is required for BSL Language Server but 'java' was not found on PATH.")

    major = _get_java_major_version(java_exe)
    if major is None:
        # detection failed; log a warning but let the LSP attempt to start
        log.warning("Could not determine Java version for '%s'; BSL LSP requires Java %d+.", java_exe, BSL_LS_MIN_JAVA_VERSION)
        return

    if major < BSL_LS_MIN_JAVA_VERSION:
        raise RuntimeError(
            f"Java {BSL_LS_MIN_JAVA_VERSION}+ is required for BSL Language Server, but '{java_exe}' is Java {major}. "
            f"Install a newer JDK (e.g. Temurin {BSL_LS_MIN_JAVA_VERSION}) and ensure it appears first on PATH "
            f"or point JAVA_HOME to it."
        )


class BSLLanguageServer(SolidLanguageServer):
    """
    BSL (1C:Enterprise / OneScript) language server integration for Serena.
    """

    def __init__(
        self,
        config: LanguageServerConfig,
        repository_root_path: str,
        solidlsp_settings: SolidLSPSettings,
    ):
        super().__init__(

View on GitHub (pinned to 7fcbca7e62)

Solutions

Install a JDK >= the minimum (e.g. Temurin BSLS_MIN_JAVA_VERSION)
Reorder PATH so the newer JDK's bin directory comes first (check `java -version`)
Point JAVA_HOME at the newer JDK and ensure $JAVA_HOME/bin is on PATH
Use a JDK version manager (sdkman/jenv) to select the required version for this project

Example fix

// before
$ java -version
openjdk version "1.8.0_312"  # too old
// after
export JAVA_HOME=/usr/lib/jvm/temurin-17-jdk
export PATH=$JAVA_HOME/bin:$PATH

Defensive patterns

Strategy: validation

Validate before calling

import shutil, re, subprocess
java = shutil.which("java")
if java:
    out = subprocess.run([java, "-version"], capture_output=True, text=True).stderr
    m = re.search(r'version "(\d+)', out)
    if m and int(m.group(1)) < 17:
        print(f"Java {m.group(1)} is too old; install JDK 17+ and put it first on PATH")

Try / catch

try:
    server = BSLLanguageServer(...)
except RuntimeError as e:
    if "is Java" in str(e) and "BSL Language Server" in str(e):
        switch_to_newer_jdk(min_version=17)  # sdkman/jenv or JAVA_HOME update, then retry
    else:
        raise

Prevention

Keep a modern JDK (17+) as the default `java` on PATH for this project
Use sdkman/jenv to pin the JDK per project so old system Java never shadows it
Check `java -version` before starting Java-based language servers

When it happens

Trigger: Calling _create_launch_command when _get_java_major_version(java_exe) returns a major < BSLS_MIN_JAVA_VERSION — e.g. PATH resolves to Java 8 or 11.

Common situations: System default Java is an old LTS (8/11) used by other tools; multiple JDKs installed with the old one first on PATH; JAVA_HOME pointing to an old JDK; macOS defaulting to legacy Apple Java.

Related errors

AI-assisted analysis of oraios/serena@7fcbca7e62 (2026-08-29). Data as JSON: /api/errors/acdbda01516afaed. Report an issue: GitHub.