This code may help you

private static RuleBase readDecisionTable() throws Exception {
final SpreadsheetCompiler converter = new SpreadsheetCompiler();
final String drl = converter.compile( "/Sample.xls", InputType.XLS );

PackageBuilder builder = new PackageBuilder();
builder.addPackageFromDrl( new StringReader( drl ) );
Package pkg = builder.getPackage();
RuleBase ruleBase = RuleBaseFactory.newRuleBase();
ruleBase.addPackage( pkg );
return ruleBase;
}

Regards,
Alex