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How can I add/compile multiple handlebar template?

I have a microservice running which reads handlebar from yml file. Right now I am working on partials where some part of my every template can be made common/re-used. Since I am reading handlebar template name from my yml file. It is one template name at a time. But how can I include/import/compile partial in Java.
Currently I am getting an error:
Partial xxx.hbs could not be found at xxx.hbs
Tried this solution:
TemplateLoader loader = new ClassPathTemplateLoader("/resources",
".hbs");
Handlebars handlebars = new Handlebars(loader);
Template template = handlebars.compile("greeting");
But I want to load a partial let say which is inside greeting.hbs.
Partial xxx.hbs could not be found at xxx.hbs

Read templates from a file StringTemplate

I'm using the template engine StringTemplate for some templates (obviously).
What I want is to be able to store the templates I have in seperate files, ofcourse I can do that with simple .txt files and reading them into a String, looks a bit like this then
ST template = new ST(readTemplateFromFile("template.txt"))
private String readTemplateFromFile(String templateFile){
//read template from file
}
But what I was wondering is if there's functionality in the StringTemplate engine to do that automatically. SO that i don't have to write code that already exists.
I've read something about Group Files but I don't quite understand that,are those like Template files? Or am I completely missing something?

Yes, there is functionality available that can be used directly without providing your own file loading code.
From the ST JavaDoc:
To use templates, you create one (usually via STGroup) and then inject attributes using add(java.lang.String, java.lang.Object). To render its attacks, use render().
To follow that advice the following code can be used.
First, create a file called exampleTemplate.stg and place it on your classpath.
templateExample(param) ::= <<
This is a template with the following param: (<param>)
>>
Then, render the template by using the following code:
// Load the file
final STGroup stGroup = new STGroupFile("exampleTemplate.stg");
// Pick the correct template
final ST templateExample = stGroup.getInstanceOf("templateExample");
// Pass on values to use when rendering
templateExample.add("param", "Hello World");
// Render
final String render = templateExample.render();
// Print
System.out.println(render);
The output is:
This is a template with the following param: (Hello World)
Some additional notes:
STGroupFile is a subclass of STGroup. There are other subclasses as well that you find out more about in the JavaDoc.
In the example above the template file was placed on the classpath. This is not a requirement, files can be placed in a relative folder or a in an absolute folder as well.

Commons configuration library to add elements

I am using the apache commons configuration library to read a configuration xml and it works nicely. However, I am not able to modify the value of the elements or add new ones.
To read the xml I use the following code:
XMLConfiguration config = new XMLConfiguration(dnsXmlPath);
boolean enabled = config.getBoolean("enabled", true));
int size = config.getInt("size");
To write I am trying to use:
config.setProperty("newProperty", "valueNewProperty");
config.save();
If I call config.getString("newProperty"), I obtain "valueNewProperty", but the xml has not been changed.
Obviously it is not the right way or I am missing something, because it does not work.
Could anybody tell me how to do this?
Thanks in advance.

You're modifying xml structure in memory
The parsed document will be stored keeping its structure. The class also tries to preserve as much information from the loaded XML document as possible, including comments and processing instructions. These will be contained in documents created by the save() methods, too.
Like other file based configuration classes this class maintains the name and path to the loaded configuration file. These properties can be altered using several setter methods, but they are not modified by save() and load() methods. If XML documents contain relative paths to other documents (e.g. to a DTD), these references are resolved based on the path set for this configuration.
You need to use XMLConfiguration.html#save(java.io.Writer) method
For example, after you've done all your modifications save it:
config.save(new PrintWriter(new File(dnsXmlPath)));
EDIT
As mentioned in comment, calling config.load() before calling setProperty() method fixes the issue.

I solved it with the following lines. I was missing the config.load().
XMLConfiguration config = new XMLConfiguration(dnsXmlPath);
config.load();
config.setProperty("newProperty", "valueNewProperty");
config.save();
It is true though that you can used the next line instead of config.save() and works the same.
config.save(new PrintWriter(new File(dnsXmlPath)));

Parse velocity variables within java

The following is an example of what I want to do.
I have a bunch of files such as test1.vm:
Welcome ${name}. This is test1.
Then I have a file called defaults.vm:
#set($name = "nmore")
I want render test1.vm (and the other test files) with the variable(s) in defaults.vm without using #parse as I would have to modify all the test files.
Is there a way to do this from within the accompanying java file?

I'm not sure if you have any constraints or any other specific requirements, but if you don't have you tried to use Velocity API? Something like this:
Context context = new VelocityContext();
Template template = Velocity.getTemplate("src/main/resources/defaults.vm");
template.merge(context, NullWriter.NULL_WRITER);
StringWriter writer = new StringWriter();
Template toBeParsedTemplate = Velocity.getTemplate("src/main/resources/test1.vm");
toBeParsedTemplate.merge(context, writer);
String renderedContent = writer.getBuffer().toString();
System.out.println(renderedContent);
The idea is that you fill in the Context object with the variables generated from defaults.vm and use the same context to evaluate test1.vm.
I've tried this using Velocity 1.7 and commons-io 2.4 (for the NullWriter) seems to be working fine, but I'm not sure if this can fit into your requirement or you're looking into other alternatvies (not using Velocity API).
More info on the Context object here:
http://velocity.apache.org/engine/devel/developer-guide.html#The_Context
Hope that helps.

Velocity, different template paths

Does anyone know if it is possible to get templates from different paths with velocity? After initialization Velocity refuses to change the "file.resource.loader.path".
This is my code:
public Generator(){
Properties p = new Properties();
p.setProperty("resource.loader", "file");
p.setProperty("file.resource.loader.class", "org.apache.velocity.runtime.resource.loader.FileResourceLoader");
p.setProperty("file.resource.loader.path", "");
Velocity.init(p);
}
The templates can be located in different locations ( the user can select one with a file dialog ). So I have this code upon fetching the template out of velocity
private Template fetch (String templatePath) {
out_println("Initializing Velocity core...");
int end = templatePath.lastIndexOf(File.separator);
Properties p = new Properties();
p.setProperty("file.resource.loader.path", templatePath.substring(0, end));
Velocity.init(p);
return Velocity.getTemplate(templatePath.substring(end+1));
}
This is not working. It seems that once Velocity is initialized it can't be reset with different properties. Any suggestions on how to solve this problem?
Possible Program flow:
User selects group that needs to be filled into the template
User selects a template to use (can be located anywhere on the hdd)
User presses generate

Velocity can be used in two ways: the singleton model or the separate instance model. You are currently using the singleton model in which only one instance of the Velocity engine in the JVM is allowed.
Instead, you should use the separate instance model which allows you to create multiple instances of Velocity in the same JVM in order to support different template directories.
VelocityEngine ve = new VelocityEngine();
ve.setProperty(RuntimeConstants.FILE_RESOURCE_LOADER_PATH, "path/to/templates");
ve.init();
Template t = ve.getTemplate("foo.vm");

Adding to the points above:
Even if one is using non-singleton model i.e using VelocityEngine object. Multiple paths can be configured by giving comma separated values to the property.
[file.resource.loader.class=path1,path2]
In such a case velocity engine will look for template in path1 first and then in path2

Consider instead of using singleton Velocity class creating and initializing new VelocityEngine before step 3.

In my case I am using Velocity with Servlets in an Eclipse Dynamic Web Project.
I couldn't actually reset the path, but I could put a subdirectory under /WebContent folder and then organize my templates that way... and have nested subdirectories as well.
RequestDispatcher requestDispatcher =
request.getRequestDispatcher("/velocity_templates/index.vm");
This simple solution was all I needed ... didn't need to mess with velocity.properties in web.xml or setting them programmatically (in each case, neither approach worked for me unfortunately when I tried).
Note that when I do template includes with #parse(..) command, I need to use the same path prefix inside the template .vm file as I did in the example code for my servlet.