FormEngines.getDefaultFormEngine() returns NULL

Flowable Engine
1

Hi,

I want to use the form engine. However, the following call is returning null. FormEngine formEngine = (FormEngine) FormEngines.getDefaultFormEngine();
I created a configuration file named flowable.form.cfg.xml as explained in the documentation. I don’t know what I’m doing wrong. I did the same to get the default process engine and everything worked as expected.

Thanks,
Clara

2

I attach the ERROR details:

11:02:28,205 [main] ERROR org.flowable.form.engine.FormEngines  - Exception while initializing form engine: liquibase/database/DatabaseConnection
java.lang.NoClassDefFoundError: liquibase/database/DatabaseConnection
	at org.flowable.form.engine.FormEngines.buildFormEngine(FormEngines.java:163)
	at org.flowable.form.engine.FormEngines.initFormEngineFromResource(FormEngines.java:144)
	at org.flowable.form.engine.FormEngines.init(FormEngines.java:76)
	at org.flowable.form.engine.FormEngines.getFormEngine(FormEngines.java:198)
	at org.flowable.form.engine.FormEngines.getDefaultFormEngine(FormEngines.java:187)
	at org.flowable.CallForForecasts.main(CallForForecasts.java:17)
Caused by: java.lang.ClassNotFoundException: liquibase.database.DatabaseConnection
	at java.net.URLClassLoader.findClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	at sun.misc.Launcher$AppClassLoader.loadClass(Unknown Source)
	at java.lang.ClassLoader.loadClass(Unknown Source)
	... 6 more

Previously I had another error:

11:08:01,036 [main] ERROR org.flowable.form.engine.FormEngines - Exception while initializing form engine: org/apache/commons/io/IOUtils
java.lang.NoClassDefFoundError: org/apache/commons/io/IOUtils

I solved it adding this dependency:

<dependency> 
	<groupId>org.apache.commons</groupId>
	<artifactId>commons-io</artifactId> 
	<version>1.3.2</version> 
</dependency>

Any idea of what could be wrong?

3

Hi Clara,

Did you include the flowable-form-engine as dependency in your project?

Best regards,

Tijs

4

Thanks @tijs, the dependency solved the error. However, now I had another one:

11:15:54,120 [main] ERROR org.flowable.form.engine.FormEngines  - Exception while initializing form engine: Error initialising form data schema
org.flowable.engine.common.api.FlowableException: Error initialising form data schema
	at org.flowable.form.engine.FormEngineConfiguration.initDbSchema(FormEngineConfiguration.java:305)
	at org.flowable.form.engine.FormEngineConfiguration.init(FormEngineConfiguration.java:191)
	at org.flowable.form.engine.FormEngineConfiguration.buildFormEngine(FormEngineConfiguration.java:174)
	at org.flowable.form.engine.FormEngines.buildFormEngine(FormEngines.java:164)
	at org.flowable.form.engine.FormEngines.initFormEngineFromResource(FormEngines.java:144)
	at org.flowable.form.engine.FormEngines.init(FormEngines.java:76)
	at org.flowable.form.engine.FormEngines.getFormEngine(FormEngines.java:198)
	at org.flowable.form.engine.FormEngines.getDefaultFormEngine(FormEngines.java:187)
	at org.flowable.CallForForecasts.main(CallForForecasts.java:17)
Caused by: liquibase.exception.ChangeLogParseException: Error Reading Migration File: Found 3 files that match org/flowable/form/db/liquibase/flowable-form-db-changelog.xml
	at liquibase.parser.core.xml.XMLChangeLogSAXParser.parseToNode(XMLChangeLogSAXParser.java:112)
	at liquibase.parser.core.xml.AbstractChangeLogParser.parse(AbstractChangeLogParser.java:17)
	at liquibase.Liquibase.getDatabaseChangeLog(Liquibase.java:229)
	at liquibase.Liquibase.update(Liquibase.java:202)
	at liquibase.Liquibase.update(Liquibase.java:192)
	at liquibase.Liquibase.update(Liquibase.java:188)
	at liquibase.Liquibase.update(Liquibase.java:181)
	at org.flowable.form.engine.FormEngineConfiguration.initDbSchema(FormEngineConfiguration.java:299)
	... 8 more
Caused by: java.io.IOException: Found 3 files that match org/flowable/form/db/liquibase/flowable-form-db-changelog.xml
	at liquibase.util.StreamUtil.singleInputStream(StreamUtil.java:205)
	at liquibase.parser.core.xml.XMLChangeLogSAXParser.parseToNode(XMLChangeLogSAXParser.java:93)
	... 15 more

I read in a post a similar situation but I don’t know it was finally solved. I checked the flowable-form-db-changelog.xml and in effect, there are 3 files with this name (I’m working with version 6.2.0).

5

Hi Clara,

Having this file 3 times on the classpath should not be possible when the dependencies are set correctly.
Could you share the dependencies of your project? Are you using Maven?

Best regards,

Tijs

6

Yes, I’m using Maven. I think that the files repetition is related to a problem that I had when I cloned the project. I’m working to solve this. In my project the only dependencies that I have are the following:

<dependency>
	<groupId>org.flowable</groupId>
	<artifactId>flowable-engine</artifactId>
	<version>6.2.0</version>
</dependency>
<dependency>
	<groupId>org.flowable</groupId>
	<artifactId>flowable-form-engine</artifactId>
	<version>6.2.0</version>
</dependency>

<dependency>
	<groupId>org.postgresql</groupId>
	<artifactId>postgresql</artifactId>
	<version>42.1.4</version>
</dependency>
<dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-api</artifactId>
	<version>1.7.21</version>
</dependency>
<dependency>
	<groupId>org.slf4j</groupId>
	<artifactId>slf4j-log4j12</artifactId>
	<version>1.7.21</version>
</dependency>

Thanks for the quick responses.

7

That looks fine. Were you able to resolve the issue with the 3 liquibase changelog files?

Best regards,

Tijs

8

I didn’t resolve it yet. I thought that I made something wrong when I build Flowable engine in Eclipse so I build it again but the error is the same (Error Reading Migration File).
I’m working to solve it, when I had any news I will update the post.

Thanks,
Clara

9

Hi,
I solved the error. The problem was that I imported JARs that were already available in the Maven Dependencies, so I just needed to remove these JARs.

Regards,
Clara

10

Hi @clara.gaset
what were those JAR’s that we have to remove?