Ansible: Assign variable if particular directory exists, else assign another value

I am trying to assign a variable to a directory only if it exists, else assign a default value.

#java
java_root: "{{ root_dir }}/java"
JAVA_HOME: "{{ java_root }}/jdk-default.version"

If a given newer JDK version is installed (given the directory name), I 'd like to assign the variable JAVA_HOME to another value.

In pseudo code

if directory exist "{{ java_root }}/jdk-x.0"
  JAVA_HOME: "{{ java_root }}/jdk-x.0"
else 
  JAVA_HOME: "{{ java_root }}/jdk-default.version"

I read about Ansible module stat but I prefer to avoid it. Not sure if the machine has module stat installed.

There is a way to avoid the Ansible module stat

It is with find .
Then the result is stored in variable jdks_dirs with register.

  tasks:
    - name: Check if the newer JDK version directory exists
      find:
        paths: "{{ java_root }}"
        patterns: "jdk-x.0"
        file_type: directory
      register: jdk_dirs

Then the conditions are defined with keyword when

 # if the directory exists
- name: Set JAVA_HOME based on directory existence
     
      set_fact:
        JAVA_HOME: "{{ java_root }}/jdk-x.0"
      when: jdk_dirs.matched > 0
# else if the directory doesn't exist
- name: Set JAVA_HOME to default if newer JDK version directory does not exist
      set_fact:
        JAVA_HOME: "{{ default_java_home }}"
      when: jdk_dirs.matched == 0
# whatever the condition, print the result
- name: Debug JAVA_HOME
      debug:
        msg: "JAVA_HOME is set to {{ JAVA_HOME }}"

Note the when conditions must be exclusive. There is no such a thing as else condition in Ansible.
There is another way to else condition.