pentaho/pentaho-kettle · error · KettleConfigException

Unable to parse expression

Error message

Unable to parse expression [<expression>] with Ognl

What it means

setOgnlProperty compiles the OGNL expression (second token of an 'ognl:expression' value) into an OgnlExpression, caching compiled expressions. This error is thrown when OGNL fails to parse the expression syntax (OgnlException), wrapped in a KettleConfigException with the offending expression text.

Solutions

1. Fix the OGNL expression syntax in the config value; test it in an OGNL evaluator first.
2. Remove colons from the expression or restructure it, since the value is split on ':' — only token[1] onward matters but splitting corrupts complex expressions.
3. Validate expression[1] with ognl.Ognl.parseExpression() in a unit test before shipping the config.
4. Catch KettleConfigException during config load and log expression[1] to pinpoint the bad config entry.

Example fix

// before
propertySetter.setProperty(obj, "name", "ognl:getNaem()");

// after
propertySetter.setProperty(obj, "name", "ognl:getName()");

try {
  org.apache.commons.ognl.Ognl.parseExpression(exprString);
} catch (Exception e) {
  throw new IllegalArgumentException("Invalid OGNL expression in config: " + exprString, e);
}

try {
  propertySetter.setProperty(obj, property, value);
} catch (KettleConfigException e) {
  LOG.error("OGNL parse failed for property " + property + ", value=" + value, e);
}

When it happens

Trigger: Calling setProperty with a value like 'ognl:<bad syntax>' where expression[1] is not valid OGNL — e.g. unbalanced parentheses, invalid identifiers, malformed method calls.

Common situations: Hand-written OGNL in config files with typos; expressions referencing removed/renamed properties that fail at parse time; colons inside the expression truncating it since the value is split on ':' before parsing.

Understand the failure class

• Parsing and encoding errors: unexpected token, malformed input — why parsers reject input and how to find the real culprit.

Related errors

• the ognl, directive need at least 2 parameters: ongl and…
• Unable to get value for expression
• A connection of type PALO is expected
• A connection of type PALO is expected
• Caught a number format exception converting minimum length…

AI-assisted analysis of pentaho/pentaho-kettle@f3058517a1 (2026-09-13). Data as JSON: /api/errors/d38797e87cd48e21. Report an issue: GitHub.

Appendix: source

Thrown at core/src/main/java/org/pentaho/di/core/config/PropertySetter.java:94

      return BaseMessages.getString( packageName, key );
    } else {
      throw new KettleConfigException(
        "the i18, directive need 3 parameters: i18n, the package name and the key, but "
          + expression.length + " parameters were found in [" + value + "]" );
    }
  }

  private Object setOgnlProperty( String[] expression, String value ) throws KettleConfigException {
    if ( expression.length >= 2 ) {
      OgnlExpression expr = ognlExpressions.get( value );
      if ( expr == null ) {
        synchronized ( ognlExpressions ) {
          try {
            expr = new OgnlExpression( expression[1] );
            ognlExpressions.put( value, expr );

          } catch ( OgnlException e ) {
            throw new KettleConfigException( "Unable to parse expression [" + expression[1] + "] with Ognl", e );
          }
        }
      }

      // evaluate
      try {
        return expr.getValue( octx, this );
      } catch ( OgnlException e ) {
        throw new KettleConfigException(
          "Unable to get value for expression [" + expression[1] + "] with Ognl", e );
      }
    } else {
      throw new KettleConfigException(
        "the ognl, directive need at least 2 parameters: ongl and the expression but "
          + expression.length + " parameters were found in [" + value + "]" );
    }
  }
}

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