private static void resolveClassForName() throws IllegalStateException {
        String expressionFactoryProperty = System.getProperty("jakarta.el.ExpressionFactory");
        String expressionFactoryClass = MappingUtils.isBlankOrNull(expressionFactoryProperty)
                ? "com.sun.el.ExpressionFactoryImpl"
                : expressionFactoryProperty;

        try {
            Class.forName(expressionFactoryClass);
        } catch (ClassNotFoundException ex) {
            throw new IllegalStateException("Failed to resolve ExpressionFactory, " + ex.getMessage(), ex);
        }
    }
Constructs a {@link ExpressionFactory} via {@link Thread#getContextClassLoader() Thread.currentThread().getContextClassLoader()}
or the provided {@link ClassLoader}

@param classLoader class loader to resolve {@link ExpressionFactory}
@return {@link ExpressionFactory} instance
@throws IllegalStateException if jakarta.el is not on the class path or a {@link ExpressionFactory} instance could not be constructed
core/src/main/java/com/github/dozermapper/core/el/ELExpressionFactory.java