public void init() {
		extPgms = new ArrayList<>(); // symbol ID group for an external program name
		originalExtMgr = originalPgm.getExternalManager();
		latestExtMgr = latestPgm.getExternalManager();
		myExtMgr = myPgm.getExternalManager();
		resultExtMgr = resultPgm.getExternalManager();
		infoBuf = new StringBuffer();

		originalResolvedSymbols = new LongLongHashtable();
		latestResolvedSymbols = new LongLongHashtable();
		myResolvedSymbols = new LongLongHashtable();

		resultToOriginalMap = new LongLongHashtable();
		resultToLatestMap = new LongLongHashtable();
		resultToMyMap = new LongLongHashtable();
	}
Manages code unit changes and conflicts between the latest versioned
program and the modified program being checked into version control.
@param mergeManager the top level merge manager for merging a program version.
@param resultPgm the program to be updated with the result of the merge.
This is the program that will actually get checked in.
@param originalPgm the program that was checked out.
@param latestPgm the latest checked-in version of the program.
@param myPgm the program requesting to be checked in.
@param latestChanges the address set of changes between original and latest versioned program.
@param myChanges the address set of changes between original and my modified program.
Ghidra/Features/Base/src/main/java/ghidra/app/merge/listing/ExternalProgramMerger.java