NOTE

An incomplete side project from Nov 2023 that I kinda finished in Jan 2025.

I left this incomplete because IntelliJ provides a context action to change multi-line strings to text blocks since Java 13 preview came in! (curb your enthusiasm score plays 🫠) Yet I believed this project had some relevance until I learned about OpenRewrite that has a Gradle plugin that lets you run a script to migrate to text blocks.

Now that I found OpenRewrite, I am currently using it for an internal project at work. So this project now rests :/

But why the name JDoctor? Well, I thought I could salvage this to make a CLI tool to parse a Java codebase and analyze it, fix some things etc. But these things are better written with OpenRewrite recipes.

Adopt Text Block

With the advent of text blocks in Java 13, we can now use triple quotes """ for multi-line strings. In an effort to adopt this in a large codebase, this project makes use of javaparser to parse existing multi-line strings and replace then with text blocks.

Problem

At my org in the large codebase we work on, I have come across several 600+ character strings containing SQL queries that are cumbersome to read at one go. Also, I have seen instances multi-line strings with too many \n line escapes and + operators to concatenate strings that look ugly.
Text blocks provide a better, more readable alternative for these cases.

Below is an example of a JPQL query

Without text block

String multiLineSqlQuery = "SELECT e "
        + "FROM Employee e "
        + "WHERE e.department = :dept "
        + "AND e.salary >= :minSalary";

With text block

String multiLineSqlQuery =  """
                    SELECT e
                    FROM Employee e
                    WHERE e.department = :dept
                        AND e.salary >= :minSalary
                    """;

Solution

The initial idea was to write an IntelliJ plugin for this but it would be platform-dependent. Hence, with javaparser, a command-line utility can be provided which would simply take the file/directory path which needs to adopt text blocks.

Finally, what does it do?

For below input Java file,

import javax.persistence.EntityManager;
import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
import java.util.List;

public class JpaExample {

    final String TAG = "JpaExample";
    public static void main(String[] args) {
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("my-persistence-unit");
        EntityManager em = emf.createEntityManager();
        int salary = 100000;

        try {
            String multiLineSqlQuery = """
                    SELECT e
                    FROM Employee e
                    WHERE e.department = :dept
                    AND e.salary >= :minSalary
                    """;

            String multiLineSqlQueryWithVariables = "SELECT e "
                    + "FROM Employee e "
                    + "WHERE e.department = :dept "
                    + "AND e.salary >= " + salary;

            Query query = em.createQuery(multiLineSqlQuery);
            query.setParameter("dept", "Sales");
            query.setParameter("minSalary", 50000);

            List<Employee> results = query.getResultList();

            for (Employee employee : results) {
                System.out.println("Employee Name: " + employee.getName());
            }
        } finally {
            em.close();
            emf.close();
        }
    }
}

You get -

import javax.persistence.EntityManagerFactory;
import javax.persistence.Persistence;
import javax.persistence.Query;
import java.util.List;

public class JpaExample {

    final String TAG = "JpaExample";

    public static void main(String[] args) {
        EntityManagerFactory emf = Persistence.createEntityManagerFactory("my-persistence-unit");
        EntityManager em = emf.createEntityManager();
        int salary = 100000;
        try {
            String multiLineSqlQuery = """
                SELECT e
                FROM Employee e
                WHERE e.department = :dept
                AND e.salary >= :minSalary
                """;
            String multiLineSqlQueryWithVariables = """
                SELECT e  FROM Employee e  WHERE e.department = :dept  AND e.salary >=  salary""";
            Query query = em.createQuery(multiLineSqlQuery);
            query.setParameter("dept", "Sales");
            query.setParameter("minSalary", 50000);
            List<Employee> results = query.getResultList();
            for (Employee employee : results) {
                System.out.println("Employee Name: " + employee.getName());
            }
        } finally {
            em.close();
            emf.close();
        }
    }
}

So, it kinda works.

I didn't fix it yet to inlining variables because this would look better if I use String.format over here. Again, finding the variable again from the parsed variable declarations with another vistor (maybe two) is a lot more effort than it is with OpenRewrite.