fix(java): recognize interface TypeKind and preserve Implements relation

lang/collect/collect.go

@@ -67,6 +67,11 @@ type Collector struct {
 	// 	symbol => [deps]
 	deps map[*DocumentSymbol][]dependency
 
+	// type symbol => list of interfaces it implements.
+	// Populated alongside c.deps but kept separately so Export can emit
+	// Type.Implements distinct from the generic SubStruct dependency list.
+	implementsRel map[*DocumentSymbol][]dependency
+
 	// variable (or const) => type
 	vars map[*DocumentSymbol]dependency
 
@@ -101,6 +106,19 @@ func (c *Collector) UseJavaIPC(conv *javaipc.Converter) {
 	c.javaIPC = conv
 }
 
+// addImplementsRel records that `from` implements `iface`. Idempotent on (from, iface).
+func (c *Collector) addImplementsRel(from *DocumentSymbol, iface *DocumentSymbol, tokenLoc Location) {
+	if from == nil || iface == nil {
+		return
+	}
+	for _, existing := range c.implementsRel[from] {
+		if existing.Symbol == iface {
+			return
+		}
+	}
+	c.implementsRel[from] = append(c.implementsRel[from], dependency{Location: tokenLoc, Symbol: iface})
+}
+
 type methodInfo struct {
 	Receiver  dependency  `json:"receiver"`
 	Interface *dependency `json:"implement,omitempty"` // which interface it implements
@@ -143,6 +161,7 @@ func NewCollector(repo string, cli *LSPClient) *Collector {
 		syms:             map[Location]*DocumentSymbol{},
 		funcs:            map[*DocumentSymbol]functionInfo{},
 		deps:             map[*DocumentSymbol][]dependency{},
+		implementsRel:    map[*DocumentSymbol][]dependency{},
 		vars:             map[*DocumentSymbol]dependency{},
 		files:            map[string]*uniast.File{},
 		fileContentCache: make(map[string]string),
@@ -760,6 +779,7 @@ func (c *Collector) ScannerByJavaIPC(ctx context.Context) ([]*DocumentSymbol, er
 				}
 				tokLoc := locFromPos(fileAbs, impl.StartLine, impl.StartColumn, impl.EndLine, impl.EndColumn)
 				addDep(classSym, depSym, tokLoc)
+				c.addImplementsRel(classSym, depSym, tokLoc)
 			}
 		} else {
 			for _, impl := range ci.ImplementsTypes {
@@ -777,6 +797,7 @@ func (c *Collector) ScannerByJavaIPC(ctx context.Context) ([]*DocumentSymbol, er
 					depSym.Kind = SKInterface
 				}
 				addDep(classSym, depSym, classSym.Location)
+				c.addImplementsRel(classSym, depSym, classSym.Location)
 			}
 		}
 
@@ -1587,6 +1608,7 @@ func (c *Collector) walk(node *sitter.Node, uri DocumentURI, content []byte, fil
 					impl.Kind = SKInterface
 					impl.Role = REFERENCE
 					c.addReferenceDeps(sym, impl)
+					c.addImplementsRel(sym, impl, impl.Location)
 				}
 			}
 		}

lang/collect/export.go

@@ -573,10 +573,29 @@ func (c *Collector) exportSymbol(repo *uniast.Repository, symbol *DocumentSymbol
 			TypeKind: mapKind(k),
 			Exported: public,
 		}
-		// collect deps
+		// Implements relationship is preserved as a first-class field rather
+		// than blended into the generic SubStruct dependency list.
+		implSyms := map[*DocumentSymbol]bool{}
+		if rels := c.implementsRel[symbol]; rels != nil {
+			for _, rel := range rels {
+				tok := ""
+				if c.cli != nil {
+					tok, _ = c.cli.Locate(rel.Location)
+				}
+				iid, err := c.exportSymbol(repo, rel.Symbol, tok, visited)
+				if err != nil {
+					continue
+				}
+				obj.Implements = append(obj.Implements, *iid)
+				implSyms[rel.Symbol] = true
+			}
+		}
 		// collect deps
 		if deps := c.deps[symbol]; deps != nil {
 			for _, dep := range deps {
+				if implSyms[dep.Symbol] {
+					continue
+				}
 				tok := ""
 				if c.cli != nil {
 					tok, _ = c.cli.Locate(dep.Location)

lang/collect/java_interface_test.go

@@ -0,0 +1,194 @@
+// Copyright 2025 CloudWeGo Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     https://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package collect
+
+import (
+	"context"
+	"path/filepath"
+	"runtime"
+	"testing"
+
+	javaipc "github.com/cloudwego/abcoder/lang/java/ipc"
+	javapb "github.com/cloudwego/abcoder/lang/java/pb"
+	"github.com/cloudwego/abcoder/lang/lsp"
+	"github.com/cloudwego/abcoder/lang/uniast"
+)
+
+// TestJavaIPC_InterfaceKindAndImplements drives the Java parser → universal AST
+// pipeline for the two regressions:
+//  1. Interface declarations must be exported with TypeKind == "interface".
+//  2. A class that "implements I" must have I in Type.Implements (and not be
+//     a plain SubStruct dependency).
+//
+// We hand-build the javaipc.Converter so the test does not require the real
+// java parser binary; it still exercises ScannerByJavaIPC + Export end-to-end
+// against the real fixture source files under testdata/java/5_interface_impl.
+func TestJavaIPC_InterfaceKindAndImplements(t *testing.T) {
+	repo := fixtureRepo(t)
+	conv := buildInterfaceFixtureConverter(repo)
+
+	cli := &lsp.LSPClient{ClientOptions: lsp.ClientOptions{Language: uniast.Java}}
+	c := NewCollector(repo, cli)
+	c.Language = uniast.Java
+	c.NeedStdSymbol = true
+	c.UseJavaIPC(conv)
+
+	if _, err := c.ScannerByJavaIPC(context.Background()); err != nil {
+		t.Fatalf("ScannerByJavaIPC failed: %v", err)
+	}
+	rep, err := c.Export(context.Background())
+	if err != nil {
+		t.Fatalf("Export failed: %v", err)
+	}
+
+	types := collectExportedTypes(rep)
+
+	animal, ok := types["Animal"]
+	if !ok {
+		t.Fatalf("Animal type not exported; got types: %v", typeNames(types))
+	}
+	if animal.TypeKind != uniast.TypeKindInterface {
+		t.Errorf("Animal.TypeKind = %q, want %q", animal.TypeKind, uniast.TypeKindInterface)
+	}
+
+	swimmer, ok := types["Swimmer"]
+	if !ok {
+		t.Fatalf("Swimmer type not exported; got types: %v", typeNames(types))
+	}
+	if swimmer.TypeKind != uniast.TypeKindInterface {
+		t.Errorf("Swimmer.TypeKind = %q, want %q", swimmer.TypeKind, uniast.TypeKindInterface)
+	}
+
+	dog, ok := types["Dog"]
+	if !ok {
+		t.Fatalf("Dog type not exported; got types: %v", typeNames(types))
+	}
+	if dog.TypeKind != uniast.TypeKindStruct {
+		t.Errorf("Dog.TypeKind = %q, want %q", dog.TypeKind, uniast.TypeKindStruct)
+	}
+	if !containsIdentityName(dog.Implements, "Animal") {
+		t.Errorf("Dog.Implements does not contain Animal; got %v", identityNames(dog.Implements))
+	}
+	if containsDependencyName(dog.SubStruct, "Animal") {
+		t.Errorf("Dog.SubStruct should not duplicate the Animal implements relation; got %v",
+			dependencyNames(dog.SubStruct))
+	}
+
+	fish, ok := types["Fish"]
+	if !ok {
+		t.Fatalf("Fish type not exported; got types: %v", typeNames(types))
+	}
+	if !containsIdentityName(fish.Implements, "Animal") {
+		t.Errorf("Fish.Implements missing Animal; got %v", identityNames(fish.Implements))
+	}
+	if !containsIdentityName(fish.Implements, "Swimmer") {
+		t.Errorf("Fish.Implements missing Swimmer; got %v", identityNames(fish.Implements))
+	}
+}
+
+// fixtureRepo returns the absolute path to testdata/java/5_interface_impl.
+func fixtureRepo(t *testing.T) string {
+	t.Helper()
+	_, thisFile, _, ok := runtime.Caller(0)
+	if !ok {
+		t.Fatalf("runtime.Caller failed")
+	}
+	return filepath.Join(filepath.Dir(thisFile), "..", "..", "testdata", "java", "5_interface_impl")
+}
+
+func buildInterfaceFixtureConverter(repo string) *javaipc.Converter {
+	conv := javaipc.NewConverter(repo, "test-mod")
+
+	srcDir := filepath.Join(repo, "src", "main", "java", "org", "example")
+	mk := func(fqcn, fname string, kind javapb.ClassType, startLine, endLine int32, implements []string) *javapb.ClassInfo {
+		return &javapb.ClassInfo{
+			ClassName:       fqcn,
+			PackageName:     "org.example",
+			FilePath:        filepath.Join(srcDir, fname),
+			ClassType:       kind,
+			ImplementsTypes: implements,
+			StartLine:       startLine,
+			StartColumn:     1,
+			EndLine:         endLine,
+			EndColumn:       2,
+			Source:          &javapb.SourceInfo{Type: javapb.SourceType_SOURCE_TYPE_LOCAL},
+		}
+	}
+	conv.LocalClassCache["org.example.Animal"] =
+		mk("org.example.Animal", "Animal.java", javapb.ClassType_CLASS_TYPE_INTERFACE, 3, 6, nil)
+	conv.LocalClassCache["org.example.Swimmer"] =
+		mk("org.example.Swimmer", "Swimmer.java", javapb.ClassType_CLASS_TYPE_INTERFACE, 3, 5, nil)
+	conv.LocalClassCache["org.example.Dog"] =
+		mk("org.example.Dog", "Dog.java", javapb.ClassType_CLASS_TYPE_CLASS, 3, 19,
+			[]string{"org.example.Animal"})
+	conv.LocalClassCache["org.example.Fish"] =
+		mk("org.example.Fish", "Fish.java", javapb.ClassType_CLASS_TYPE_CLASS, 3, 23,
+			[]string{"org.example.Animal", "org.example.Swimmer"})
+	return conv
+}
+
+func collectExportedTypes(rep *uniast.Repository) map[string]*uniast.Type {
+	out := map[string]*uniast.Type{}
+	for _, mod := range rep.Modules {
+		for _, pkg := range mod.Packages {
+			for _, ty := range pkg.Types {
+				out[ty.Identity.Name] = ty
+			}
+		}
+	}
+	return out
+}
+
+func typeNames(m map[string]*uniast.Type) []string {
+	out := make([]string, 0, len(m))
+	for k := range m {
+		out = append(out, k)
+	}
+	return out
+}
+
+func containsIdentityName(ids []uniast.Identity, name string) bool {
+	for _, id := range ids {
+		if id.Name == name {
+			return true
+		}
+	}
+	return false
+}
+
+func identityNames(ids []uniast.Identity) []string {
+	out := make([]string, 0, len(ids))
+	for _, id := range ids {
+		out = append(out, id.Name)
+	}
+	return out
+}
+
+func containsDependencyName(deps []uniast.Dependency, name string) bool {
+	for _, d := range deps {
+		if d.Identity.Name == name {
+			return true
+		}
+	}
+	return false
+}
+
+func dependencyNames(deps []uniast.Dependency) []string {
+	out := make([]string, 0, len(deps))
+	for _, d := range deps {
+		out = append(out, d.Identity.Name)
+	}
+	return out
+}

testdata/java/0_simple/pom.xml

@@ -0,0 +1,15 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>simple</groupId>
+    <artifactId>simple</artifactId>
+    <version>1.0.0</version>
+    <packaging>jar</packaging>
+
+    <build>
+        <sourceDirectory>.</sourceDirectory>
+    </build>
+</project>

testdata/java/1_advanced/pom.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.example</groupId>
+    <artifactId>advanced</artifactId>
+    <version>1.0.0</version>
+    <packaging>jar</packaging>
+</project>

testdata/java/2_inheritance/pom.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.example</groupId>
+    <artifactId>inheritance</artifactId>
+    <version>1.0.0</version>
+    <packaging>jar</packaging>
+</project>

testdata/java/5_interface_impl/pom.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project xmlns="http://maven.apache.org/POM/4.0.0"
+         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
+         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
+    <modelVersion>4.0.0</modelVersion>
+
+    <groupId>org.example</groupId>
+    <artifactId>interface-impl</artifactId>
+    <version>1.0.0</version>
+    <packaging>jar</packaging>
+</project>

testdata/java/5_interface_impl/src/main/java/org/example/Animal.java

@@ -0,0 +1,6 @@
+package org.example;
+
+public interface Animal {
+    void eat();
+    String name();
+}

testdata/java/5_interface_impl/src/main/java/org/example/Dog.java

@@ -0,0 +1,19 @@
+package org.example;
+
+public class Dog implements Animal {
+    private final String n;
+
+    public Dog(String n) {
+        this.n = n;
+    }
+
+    @Override
+    public void eat() {
+        System.out.println(n + " eats.");
+    }
+
+    @Override
+    public String name() {
+        return n;
+    }
+}

testdata/java/5_interface_impl/src/main/java/org/example/Fish.java

@@ -0,0 +1,24 @@
+package org.example;
+
+public class Fish implements Animal, Swimmer {
+    private final String n;
+
+    public Fish(String n) {
+        this.n = n;
+    }
+
+    @Override
+    public void eat() {
+        System.out.println(n + " eats.");
+    }
+
+    @Override
+    public void swim() {
+        System.out.println(n + " swims.");
+    }
+
+    @Override
+    public String name() {
+        return n;
+    }
+}

testdata/java/5_interface_impl/src/main/java/org/example/Swimmer.java

@@ -0,0 +1,5 @@
+package org.example;
+
+public interface Swimmer {
+    void swim();
+}