diff --git a/src/dynamic/lang/go.rs b/src/dynamic/lang/go.rs
index ed11ce57..33678521 100644
--- a/src/dynamic/lang/go.rs
+++ b/src/dynamic/lang/go.rs
@@ -622,7 +622,11 @@ func main() {{
         filename: "main.go".to_owned(),
         command: vec!["./nyx_harness".to_owned()],
         extra_files: vec![("go.mod".to_owned(), go_mod)],
-        entry_subpath: None,
+        // Park the fixture under `entry/` so `go build .` only picks up
+        // the synthetic `main.go` — fixtures declare `package vuln` /
+        // `package benign`, which would otherwise collide with the
+        // harness's `package main` and break the build.
+        entry_subpath: Some("entry/entry.go".to_owned()),
     }
 }
 
@@ -684,7 +688,11 @@ func main() {{
         filename: "main.go".to_owned(),
         command: vec!["./nyx_harness".to_owned()],
         extra_files: vec![("go.mod".to_owned(), go_mod)],
-        entry_subpath: None,
+        // Park the fixture under `entry/` so `go build .` only picks up
+        // the synthetic `main.go` — fixtures declare `package vuln` /
+        // `package benign`, which would otherwise collide with the
+        // harness's `package main` and break the build.
+        entry_subpath: Some("entry/entry.go".to_owned()),
     }
 }
 
@@ -744,7 +752,11 @@ func main() {{
         filename: "main.go".to_owned(),
         command: vec!["./nyx_harness".to_owned()],
         extra_files: vec![("go.mod".to_owned(), go_mod)],
-        entry_subpath: None,
+        // Park the fixture under `entry/` so `go build .` only picks up
+        // the synthetic `main.go` — fixtures declare `package vuln` /
+        // `package benign`, which would otherwise collide with the
+        // harness's `package main` and break the build.
+        entry_subpath: Some("entry/entry.go".to_owned()),
     }
 }
 
diff --git a/src/dynamic/lang/java.rs b/src/dynamic/lang/java.rs
index 326b43de..66140106 100644
--- a/src/dynamic/lang/java.rs
+++ b/src/dynamic/lang/java.rs
@@ -1239,8 +1239,9 @@ public class NyxHarness {{
 /// *unmodified* value bytes (including any embedded `\r\n`) via a
 /// `ProbeKind::HeaderEmit` probe.  Mirrors the synthetic-harness
 /// pattern used by Phase 03 / 04 / 05 / 06 / 07.
-pub fn emit_header_injection_harness(_spec: &HarnessSpec) -> HarnessSource {
+pub fn emit_header_injection_harness(spec: &HarnessSpec) -> HarnessSource {
     let shim = probe_shim();
+    let extra_files = servlet_stubs_for_entry(&spec.entry_file);
     let source = format!(
         r#"// Nyx dynamic harness — HEADER_INJECTION HttpServletResponse.setHeader (Phase 08 / Track J.6).
 import java.io.FileWriter;
@@ -1307,7 +1308,7 @@ public class NyxHarness {{
             ".".to_owned(),
             "NyxHarness".to_owned(),
         ],
-        extra_files: Vec::new(),
+        extra_files,
         entry_subpath: None,
     }
 }
@@ -1320,8 +1321,9 @@ public class NyxHarness {{
 /// `Location:` value plus the request's origin host via a
 /// `ProbeKind::Redirect` probe.  Mirrors the synthetic-harness
 /// pattern used by Phase 03 / 04 / 05 / 06 / 07 / 08.
-pub fn emit_open_redirect_harness(_spec: &HarnessSpec) -> HarnessSource {
+pub fn emit_open_redirect_harness(spec: &HarnessSpec) -> HarnessSource {
     let shim = probe_shim();
+    let extra_files = servlet_stubs_for_entry(&spec.entry_file);
     let source = format!(
         r#"// Nyx dynamic harness — OPEN_REDIRECT HttpServletResponse.sendRedirect (Phase 09 / Track J.7).
 import java.io.FileWriter;
@@ -1386,11 +1388,28 @@ public class NyxHarness {{
             ".".to_owned(),
             "NyxHarness".to_owned(),
         ],
-        extra_files: Vec::new(),
+        extra_files,
         entry_subpath: None,
     }
 }
 
+/// Stage the `javax.servlet.*` / `jakarta.servlet.*` stub bundle when
+/// the entry source imports either namespace.  Phase 08 / 09 fixtures
+/// (`HttpServletResponse.setHeader` / `.sendRedirect`) carry the
+/// `import javax.servlet.http.HttpServletResponse;` so `javac` over
+/// the workdir's `*.java` set needs the symbols on the classpath even
+/// though `NyxHarness.java` itself uses no servlet types.  Without the
+/// stubs the verifier flips to `BuildFailed` and the per-lang e2e
+/// tests silently skip via the SKIP-on-`BuildFailed` branch.
+fn servlet_stubs_for_entry(entry_file: &str) -> Vec<(String, String)> {
+    let entry_source = read_entry_source(entry_file);
+    if entry_source.contains("javax.servlet") || entry_source.contains("jakarta.servlet") {
+        crate::dynamic::lang::java_servlet_stubs::servlet_stub_files()
+    } else {
+        Vec::new()
+    }
+}
+
 /// Public wrapper to detect the shape for a finalised `HarnessSpec`,
 /// reading the entry file from disk.  Exposed so test helpers can pin a
 /// per-fixture shape without round-tripping through [`emit`].