A tool for comparing some basic AST differences between two similar Java source files.

The differences detected fall into one of six categories:

1. AM: Add a new method
2. DM: Delete a method
3. CM: Change the body of a method.
4. AF: Add a field
5. DF: Delete a field
6. CFI: Change the definition of a field initializer: i. Add an initialization on a field where there was none. ii. Deleting an initialization on a field where there was one. iii. Changing the initialization expression. iv. Changing a field's modifier (e.g. private to public).

To build and install the project to the local Maven repository, run the following from the directory containing pom.xml:

$ mvn clean install

To run the Main class on two test .java files, run the following from the directory containing pom.xml:

mvn exec:java --quiet -Dexec.args="src/test/jsrcdiff/BasicsWithMethodBody.java src/test/jsrcdiff/BasicsWithMethodBody-diff.java"

Definitions

Field Definitions

Field Key

We define a field key as a string concatenation of:

• type
• ID (AKA variable name)

Field Value

We define a field value as a string concatenation of:

• space-delimited qualifiers (e.g. "public static final")
• initializers

Method Definitions

Method Key

We define a method key as a concatenated string of the method return type, the method ID (AKA method name) and the variable types in the method argument list (e.g. "int, String, HashMap<String, String>").

Method Value

We define a method value as a concatenated string of the IDs (AKA variable names) of method arguments, qualifiers (e.g. "public static final"), and the text body of the method.

NOTE: We don't actually parse the method body, opting instead of a naive string comparison.

Operator Definitions

AM: Add a new method

We define a method as "Added" when the method key is not present in class 1, but the method key is present in class 2.

DM: Delete a method

We define a method as "Deleted" when the method key is present in class 1, but the method key is not present in class 2.

CM: Change a method

We define a method as "Changed" when the method key is present in both class 1 and 2, but the method value has changed.

AF: Add a field

We define a field as "Added" if the field key is not present in class 1, but the field key is present in class 2.

DF: Delete a field

We define a field as "Deleted" if the field key is present in class 1, but the field key is not present in class 2.

CFI: Change field initializer

We define a field as "Changed" if the field key is present in both class 1 and 2, but the field value has changed.