diff --git a/src/main/java/net/fabricmc/loom/configuration/providers/forge/MinecraftPatchedProvider.java b/src/main/java/net/fabricmc/loom/configuration/providers/forge/MinecraftPatchedProvider.java
index 03004541..02a5cce4 100644
--- a/src/main/java/net/fabricmc/loom/configuration/providers/forge/MinecraftPatchedProvider.java
+++ b/src/main/java/net/fabricmc/loom/configuration/providers/forge/MinecraftPatchedProvider.java
@@ -518,7 +518,7 @@ public class MinecraftPatchedProvider extends DependencyProvider {
 		}
 
 		getProject().javaexec(spec -> {
-			spec.setMain("net.minecraftforge.accesstransformer.TransformerProcessor");
+			spec.getMainClass().set("net.minecraftforge.accesstransformer.TransformerProcessor");
 			spec.setArgs(args);
 			spec.setClasspath(classpath);
 
diff --git a/src/main/java/net/fabricmc/loom/util/srg/SpecialSourceExecutor.java b/src/main/java/net/fabricmc/loom/util/srg/SpecialSourceExecutor.java
index 2114a57a..13ffa72a 100644
--- a/src/main/java/net/fabricmc/loom/util/srg/SpecialSourceExecutor.java
+++ b/src/main/java/net/fabricmc/loom/util/srg/SpecialSourceExecutor.java
@@ -123,7 +123,7 @@ public class SpecialSourceExecutor {
 				spec.setArgs(Arrays.asList(args));
 				spec.setClasspath(classpath);
 				spec.workingDir(workingDir.toFile());
-				spec.setMain("net.md_5.specialsource.SpecialSource");
+				spec.getMainClass().set("net.md_5.specialsource.SpecialSource");
 
 				// if running with INFO or DEBUG logging
 				if (project.getGradle().getStartParameter().getShowStacktrace() != ShowStacktrace.INTERNAL_EXCEPTIONS
@@ -163,7 +163,7 @@ public class SpecialSourceExecutor {
 				spec.setArgs(args);
 				spec.setClasspath(classpath);
 				spec.workingDir(workingDir.toFile());
-				spec.setMain("org.cadixdev.vignette.VignetteMain");
+				spec.getMainClass().set("org.cadixdev.vignette.VignetteMain");
 
 				// if running with INFO or DEBUG logging
 				if (project.getGradle().getStartParameter().getShowStacktrace() != ShowStacktrace.INTERNAL_EXCEPTIONS