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arangodb/Documentation/Books/Drivers/Java/Reference/Graph/EdgeCollection.md

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<!-- don't edit here, its from https://@github.com/arangodb/arangodb-java-driver.git / docs/Drivers/ -->
# Manipulating the edge collection
## ArangoGraph.edgeCollection
```
ArangoGraph.edgeCollection(String name) : ArangoEdgeColleciton
```
Returns a _ArangoEdgeCollection_ instance for the given edge collection name.
**Arguments**
- **name**: `String`
Name of the edge collection
**Examples**
```Java
ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");
ArangoGraph graph = db.graph("some-graph");
ArangoEdgeCollection collection = graph.edgeCollection("some-edge-collection");
```
## ArangoGraph.getEdgeDefinitions
```
ArangoGraph.getEdgeDefinitions() : Collection<String>
```
Fetches all edge collections from the graph and returns a list of collection names.
**Examples**
```Java
ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");
ArangoGraph graph = db.graph("some-graph");
Collection<String> collections = graph.getEdgeDefinitions();
```
## ArangoGraph.addEdgeDefinition
```
ArangoGraph.addEdgeDefinition(EdgeDefinition definition) : GraphEntity
```
Adds the given edge definition to the graph.
**Arguments**
- **definition**: `EdgeDefinition`
The edge definition
**Examples**
```Java
ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");
ArangoGraph graph = db.graph("some-graph");
EdgeDefinition edgeDefinition = new EdgeDefinition()
.collection("edges")
.from("start-vertices")
.to("end-vertices");
graph.addEdgeDefinition(edgeDefinition);
// the edge definition has been added to the graph
```
## ArangoGraph.replaceEdgeDefinition
```
ArangoGraph.replaceEdgeDefinition(EdgeDefinition definition) : GraphEntity
```
Change one specific edge definition. This will modify all occurrences of this definition in all graphs known to your database.
**Arguments**
- **definition**: `EdgeDefinition`
The edge definition
**Examples**
```Java
ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");
ArangoGraph graph = db.graph("some-graph");
EdgeDefinition edgeDefinition = new EdgeDefinition()
.collection("edges")
.from("start-vertices")
.to("end-vertices");
graph.replaceEdgeDefinition(edgeDefinition);
// the edge definition has been modified
```
## ArangoGraph.removeEdgeDefinition
```
ArangoGraph.removeEdgeDefinition(String definitionName) : GraphEntity
```
Remove one edge definition from the graph. This will only remove the edge collection, the vertex collections remain untouched and can still be used in your queries.
**Arguments**
- **definitionName**: `String`
The name of the edge collection used in the definition
**Examples**
```Java
ArangoDB arango = new ArangoDB.Builder().build();
ArangoDatabase db = arango.db("myDB");
ArangoGraph graph = db.graph("some-graph");
EdgeDefinition edgeDefinition = new EdgeDefinition()
.collection("edges")
.from("start-vertices")
.to("end-vertices");
graph.addEdgeDefinition(edgeDefinition);
// the edge definition has been added to the graph
graph.removeEdgeDefinition("edges");
// the edge definition has been removed
```