# CronetEngine.Builder


```
public class CronetEngine.Builder
```

<br />

*** ** * ** ***

A builder for `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine`s, which allows runtime configuration of `
CronetEngine`. Configuration options are set on the builder and then `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#build()` is called to create the `CronetEngine`.

## Summary

| ### Nested types |
|---|
| `public abstract class https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder.LibraryLoader` **This class is deprecated.** System.loadLibrary was unreliable on minSDK \<= 23, and this method was used to provide alternative, more reliable loaders. <br /> |

| ### Constants |
|---|---|
| `static final int` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#HTTP_CACHE_DISABLED() = 0` Setting to disable HTTP cache. |
| `static final int` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#HTTP_CACHE_DISK() = 3` Setting to enable on-disk cache, including HTTP data. |
| `static final int` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#HTTP_CACHE_DISK_NO_HTTP() = 2` Setting to enable on-disk cache, excluding HTTP data. |
| `static final int` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#HTTP_CACHE_IN_MEMORY() = 1` Setting to enable in-memory HTTP cache, including HTTP data. |

| ### Protected fields |
|---|---|
| `https://developer.android.com/reference/org/json/JSONObject.html` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#mParsedExperimentalOptions()` JSON representation of the experimental options. |

| ### Public constructors |
|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#Builder(android.content.Context)(https://developer.android.com/reference/android/content/Context.html context)` Constructs a `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` object that facilitates creating a `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine`. |

| ### Public methods |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#addPublicKeyPins(java.lang.String,java.util.Set<byte[]>,boolean,java.util.Date)( https://developer.android.com/reference/java/lang/String.html hostName, https://developer.android.com/reference/java/util/Set.html<byte[]> pinsSha256, boolean includeSubdomains, https://developer.android.com/reference/java/util/Date.html expirationDate )` Pins a set of public keys for a given host. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#addQuicHint(java.lang.String,int,int)(https://developer.android.com/reference/java/lang/String.html host, int port, int alternatePort)` Adds hint that `host` supports QUIC. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#build()()` Build a `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine` using this builder's configuration. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableBrotli(boolean)(boolean value)` Sets whether [Brotli](https://tools.ietf.org/html/rfc7932) compression is enabled. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableHttp2(boolean)(boolean value)` Sets whether [HTTP/2](https://tools.ietf.org/html/rfc7540) protocol is enabled. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableHttpCache(int,long)(int cacheMode, long maxSize)` Enables or disables caching of HTTP data and other information like QUIC server information. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableNetworkQualityEstimator(boolean)(boolean value)` Enables the network quality estimator, which collects and reports measurements of round trip time (RTT) and downstream throughput at various layers of the network stack. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enablePublicKeyPinningBypassForLocalTrustAnchors(boolean)(boolean value)` Enables or disables public key pinning bypass for local trust anchors. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableQuic(boolean)(boolean value)` Sets whether [QUIC](https://www.chromium.org/quic) protocol is enabled. |
| `https://developer.android.com/reference/java/lang/String.html` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#getDefaultUserAgent()()` Constructs a User-Agent string including application name and version, system build version, model and id, and Cronet version. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `@https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ConnectionMigrationOptions.Experimental https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setConnectionMigrationOptions(org.chromium.net.ConnectionMigrationOptions.Builder)( https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ConnectionMigrationOptions.Builder connectionMigrationOptionsBuilder )` |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `@https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ConnectionMigrationOptions.Experimental https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setConnectionMigrationOptions(org.chromium.net.ConnectionMigrationOptions)( https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ConnectionMigrationOptions connectionMigrationOptions )` Configures the behavior of connection migration. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `@https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/DnsOptions.Experimental https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setDnsOptions(org.chromium.net.DnsOptions)(https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/DnsOptions dnsOptions)` Configures the behavior of hostname lookup. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `@https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/DnsOptions.Experimental https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setDnsOptions(org.chromium.net.DnsOptions.Builder)(https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/DnsOptions.Builder dnsOptions)` |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `[setLibraryLoader](https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setLibraryLoader(org.chromium.net.CronetEngine.Builder.LibraryLoader))(https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder.LibraryLoader loader)` **This method is deprecated.** System.loadLibrary was unreliable on minSDK \<= 23, and this method was used to provide alternative, more reliable loaders. <br /> |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setProxyOptions(org.chromium.net.ProxyOptions)(@https://developer.android.com/reference/androidx/annotation/NonNull.html https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ProxyOptions proxyOptions)` Configures proxying behavior. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `@https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/QuicOptions.Experimental https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setQuicOptions(org.chromium.net.QuicOptions.Builder)(https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/QuicOptions.Builder quicOptionsBuilder)` |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `@https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/QuicOptions.Experimental https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setQuicOptions(org.chromium.net.QuicOptions)(https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/QuicOptions quicOptions)` Configures the behavior of Cronet when using QUIC. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setStoragePath(java.lang.String)(https://developer.android.com/reference/java/lang/String.html value)` Sets directory for HTTP Cache and Cookie Storage. |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `[setThreadPriority](https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setThreadPriority(int))(int priority)` **This method is deprecated.** On modern versions of Cronet, this method does nothing. <br /> |
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setUserAgent(java.lang.String)(https://developer.android.com/reference/java/lang/String.html userAgent)` Overrides the User-Agent header for all requests. |

## Constants

### HTTP_CACHE_DISABLED

```
public static final int HTTP_CACHE_DISABLED = 0
```

Setting to disable HTTP cache. Some data may still be temporarily stored in memory. Passed to `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableHttpCache(int,long)`.

### HTTP_CACHE_DISK

```
public static final int HTTP_CACHE_DISK = 3
```

Setting to enable on-disk cache, including HTTP data. `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setStoragePath(java.lang.String)` must be called prior to passing this constant to `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableHttpCache(int,long)`.

### HTTP_CACHE_DISK_NO_HTTP

```
public static final int HTTP_CACHE_DISK_NO_HTTP = 2
```

Setting to enable on-disk cache, excluding HTTP data. `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setStoragePath(java.lang.String)` must be called prior to passing this constant to `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableHttpCache(int,long)`.

### HTTP_CACHE_IN_MEMORY

```
public static final int HTTP_CACHE_IN_MEMORY = 1
```

Setting to enable in-memory HTTP cache, including HTTP data. Passed to `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableHttpCache(int,long)`.

## Protected fields

### mParsedExperimentalOptions

```
protected JSONObject mParsedExperimentalOptions
```

JSON representation of the experimental options.

## Public constructors

### Builder

```
public Builder(Context context)
```

Constructs a `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` object that facilitates creating a `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine`. The default configuration enables HTTP/2 and QUIC, but disables the HTTP cache.

| Parameters |
|---|---|
| `https://developer.android.com/reference/android/content/Context.html context` | Android `https://developer.android.com/reference/android/content/Context.html`, which is used by `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` to retrieve the application context. A reference to only the application context will be kept, so as to avoid extending the lifetime of `context` unnecessarily. |

## Public methods

### addPublicKeyPins

```
public CronetEngine.Builder addPublicKeyPins(
    String hostName,
    Set<byte[]> pinsSha256,
    boolean includeSubdomains,
    Date expirationDate
)
```

Pins a set of public keys for a given host. By pinning a set of public keys, `
pinsSha256`, communication with `hostName` is required to authenticate with a certificate with a public key from the set of pinned ones. An app can pin the public key of the root certificate, any of the intermediate certificates or the end-entry certificate. Authentication will fail and secure communication will not be established if none of the public keys is present in the host's certificate chain, even if the host attempts to authenticate with a certificate allowed by the device's trusted store of certificates.

Calling this method multiple times with the same host name overrides the previously set pins for the host.

More information about the public key pinning can be found in [RFC 7469](https://tools.ietf.org/html/rfc7469).

| Parameters |
|---|---|
| `https://developer.android.com/reference/java/lang/String.html hostName` | name of the host to which the public keys should be pinned. A host that consists only of digits and the dot character is treated as invalid. |
| `https://developer.android.com/reference/java/util/Set.html<byte[]> pinsSha256` | a set of pins. Each pin is the SHA-256 cryptographic hash of the DER-encoded ASN.1 representation of the Subject Public Key Info (SPKI) of the host's X.509 certificate. Use `https://developer.android.com/reference/java/security/cert/Certificate.html#getPublicKey()` and `https://developer.android.com/reference/java/security/Key.html#getEncoded()` to obtain DER-encoded ASN.1 representation of the SPKI. Although, the method does not mandate the presence of the backup pin that can be used if the control of the primary private key has been lost, it is highly recommended to supply one. |
| `boolean includeSubdomains` | indicates whether the pinning policy should be applied to subdomains of `hostName`. |
| `https://developer.android.com/reference/java/util/Date.html expirationDate` | specifies the expiration date for the pins. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

| Throws |
|---|---|
| `https://developer.android.com/reference/java/lang/NullPointerException.html` | if any of the input parameters are `null`. |
| `https://developer.android.com/reference/java/lang/IllegalArgumentException.html` | if the given host name is invalid or `pinsSha256` contains a byte array that does not represent a valid SHA-256 hash. |

### addQuicHint

```
public CronetEngine.Builder addQuicHint(String host, int port, int alternatePort)
```

Adds hint that `host` supports QUIC. Note that `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableHttpCache(int,long)` (`https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#HTTP_CACHE_DISK()`) is needed to take advantage of 0-RTT connection establishment between sessions.

| Parameters |
|---|---|
| `https://developer.android.com/reference/java/lang/String.html host` | hostname of the server that supports QUIC. |
| `int port` | host of the server that supports QUIC. |
| `int alternatePort` | alternate port to use for QUIC. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### build

```
public CronetEngine build()
```

Build a `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine` using this builder's configuration.

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine` | constructed `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine`. |

### enableBrotli

```
public CronetEngine.Builder enableBrotli(boolean value)
```

Sets whether [Brotli](https://tools.ietf.org/html/rfc7932) compression is enabled. If enabled, Brotli will be advertised in Accept-Encoding request headers. Defaults to disabled.

| Parameters |
|---|---|
| `boolean value` | `true` to enable Brotli, `false` to disable. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### enableHttp2

```
public CronetEngine.Builder enableHttp2(boolean value)
```

Sets whether [HTTP/2](https://tools.ietf.org/html/rfc7540) protocol is enabled. Defaults to enabled.

| Parameters |
|---|---|
| `boolean value` | `true` to enable HTTP/2, `false` to disable. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### enableHttpCache

```
public CronetEngine.Builder enableHttpCache(int cacheMode, long maxSize)
```

Enables or disables caching of HTTP data and other information like QUIC server information.

| Parameters |
|---|---|
| `int cacheMode` | control location and type of cached data. Must be one of `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#HTTP_CACHE_DISABLED()`. |
| `long maxSize` | maximum size in bytes used to cache data (advisory and maybe exceeded at times). |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### enableNetworkQualityEstimator

```
public CronetEngine.Builder enableNetworkQualityEstimator(boolean value)
```

Enables the network quality estimator, which collects and reports measurements of round trip time (RTT) and downstream throughput at various layers of the network stack. After enabling the estimator, listeners of RTT and throughput can be added with `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine#addRttListener(org.chromium.net.NetworkQualityRttListener)` and `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine#addThroughputListener(org.chromium.net.NetworkQualityThroughputListener)` and removed with `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine#removeRttListener(org.chromium.net.NetworkQualityRttListener)` and `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine#removeThroughputListener(org.chromium.net.NetworkQualityThroughputListener)`. The estimator uses memory and CPU only when enabled.

| Parameters |
|---|---|
| `boolean value` | `true` to enable network quality estimator, `false` to disable. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### enablePublicKeyPinningBypassForLocalTrustAnchors

```
public CronetEngine.Builder enablePublicKeyPinningBypassForLocalTrustAnchors(boolean value)
```

Enables or disables public key pinning bypass for local trust anchors. Disabling the bypass for local trust anchors is highly discouraged since it may prohibit the app from communicating with the pinned hosts. E.g., a user may want to send all traffic through an SSL enabled proxy by changing the device proxy settings and adding the proxy certificate to the list of local trust anchor. Disabling the bypass will most likely prevent the app from sending any traffic to the pinned hosts. For more information see 'How does key pinning interact with local proxies and filters?' at https://www.chromium.org/Home/chromium-security/security-faq

| Parameters |
|---|---|
| `boolean value` | `true` to enable the bypass, `false` to disable. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### enableQuic

```
public CronetEngine.Builder enableQuic(boolean value)
```

Sets whether [QUIC](https://www.chromium.org/quic) protocol is enabled. Defaults to enabled. If QUIC is enabled, then QUIC User Agent Id containing application name and Cronet version is sent to the server.

| Parameters |
|---|---|
| `boolean value` | `true` to enable QUIC, `false` to disable. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### getDefaultUserAgent

```
public String getDefaultUserAgent()
```

Constructs a User-Agent string including application name and version, system build version, model and id, and Cronet version.

| Returns |
|---|---|
| `https://developer.android.com/reference/java/lang/String.html` | User-Agent string. |

### setConnectionMigrationOptions

```
@ConnectionMigrationOptions.Experimental
public CronetEngine.Builder setConnectionMigrationOptions(
    ConnectionMigrationOptions.Builder connectionMigrationOptionsBuilder
)
```

| See also |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setConnectionMigrationOptions(org.chromium.net.ConnectionMigrationOptions)` |   |

### setConnectionMigrationOptions

```
@ConnectionMigrationOptions.Experimental
public CronetEngine.Builder setConnectionMigrationOptions(
    ConnectionMigrationOptions connectionMigrationOptions
)
```

Configures the behavior of connection migration. For more details, see documentation of `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ConnectionMigrationOptions` and the individual methods of `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ConnectionMigrationOptions.Builder`.

Only relevant if `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableQuic(boolean)` is enabled.

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### setDnsOptions

```
@DnsOptions.Experimental
public CronetEngine.Builder setDnsOptions(DnsOptions dnsOptions)
```

Configures the behavior of hostname lookup. For more details, see documentation of `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/DnsOptions` and the individual methods of `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/DnsOptions.Builder`.

Only relevant if `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableQuic(boolean)` is enabled.

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### setDnsOptions

```
@DnsOptions.Experimental
public CronetEngine.Builder setDnsOptions(DnsOptions.Builder dnsOptions)
```

| See also |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setDnsOptions(org.chromium.net.DnsOptions)` |   |

### setLibraryLoader

```
public CronetEngine.Builder [setLibraryLoader](https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setLibraryLoader(org.chromium.net.CronetEngine.Builder.LibraryLoader))(CronetEngine.Builder.LibraryLoader loader)
```

> [!CAUTION]
> **This method is deprecated.**   
>
> System.loadLibrary was unreliable on minSDK \<= 23, and this method was used to provide alternative, more reliable loaders. Now that Cronet's minSDK = 24 this method is obsolete and is a no-op.

Sets a `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder.LibraryLoader` to be used to load the native library. If not set, the library will be loaded using `https://developer.android.com/reference/java/lang/System.html#loadLibrary(java.lang.String)`.

| Parameters |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder.LibraryLoader loader` | `LibraryLoader` to be used to load the native library. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### setProxyOptions

```
public CronetEngine.Builder setProxyOptions(@NonNull ProxyOptions proxyOptions)
```

Configures proxying behavior. This affects, in different ways: connections establishment, `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/UrlRequest` and `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/BidirectionalStream`. For more details, refer to the documentation of `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/Proxy`.

This is not to be confused with proxy configuration that have been set up by: the user; or some enterprise profile configuration, or (most likely) some network autoconfiguration (e.g., Web Proxy Auto-Discovery Protocol). This is usually referred to as "system" proxy configuration. If present, respecting the system proxy configuration is often a requirement to obtain local and/or internet connectivity. CronetEngine already handles the system proxy configuration internally.

A proxy configuration defined via this API are refererred to as "app" proxy configuration. App and system proxy configuration are separate and, most importantly, differ. Currently, app and system proxy configurations are mutually exclusive: specifying `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ProxyOptions` overrides the system proxy configuration, if present. This might cause connectivity problems in some scenarios where a system proxy configuration is present. In such scenarios, users might end up with no internet access, unless `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ProxyOptions` has been configured with a final, `null`, fallback. Refer to `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ProxyOptions` documentation.

| Parameters |
|---|---|
| `@https://developer.android.com/reference/androidx/annotation/NonNull.html https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/ProxyOptions proxyOptions` | ProxyOptions to be used for `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/UrlRequest`, BiridirectionalStream and connections established by the `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine` created by this builder. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

| Throws |
|---|---|
| `https://developer.android.com/reference/java/lang/UnsupportedOperationException.html` | if the Cronet implementation being used is too old to support ProxyOptions. |

### setQuicOptions

```
@QuicOptions.Experimental
public CronetEngine.Builder setQuicOptions(QuicOptions.Builder quicOptionsBuilder)
```

| See also |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setQuicOptions(org.chromium.net.QuicOptions)` |   |

### setQuicOptions

```
@QuicOptions.Experimental
public CronetEngine.Builder setQuicOptions(QuicOptions quicOptions)
```

Configures the behavior of Cronet when using QUIC. For more details, see documentation of `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/QuicOptions` and the individual methods of `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/QuicOptions.Builder`.

Only relevant if `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#enableQuic(boolean)` is enabled.

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### setStoragePath

```
public CronetEngine.Builder setStoragePath(String value)
```

Sets directory for HTTP Cache and Cookie Storage. The directory must exist.

**NOTE:** Do not use the same storage directory with more than one `
CronetEngine` at a time. Access to the storage directory does not support concurrent access by multiple `CronetEngine`s.

| Parameters |
|---|---|
| `https://developer.android.com/reference/java/lang/String.html value` | path to existing directory. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### setThreadPriority

```
public CronetEngine.Builder [setThreadPriority](https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder#setThreadPriority(int))(int priority)
```

> [!CAUTION]
> **This method is deprecated.**   
>
> On modern versions of Cronet, this method does nothing.

Sets the thread priority of Cronet's internal thread.

| Parameters |
|---|---|
| `int priority` | the thread priority of Cronet's internal thread. A Linux priority level, from -20 for highest scheduling priority to 19 for lowest scheduling priority. For more information on values, see `https://developer.android.com/reference/android/os/Process.html#setThreadPriority(int, int)` and `https://developer.android.com/reference/android/os/Process.html#THREAD_PRIORITY_DEFAULT` values. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |

### setUserAgent

```
public CronetEngine.Builder setUserAgent(String userAgent)
```

Overrides the User-Agent header for all requests. An explicitly set User-Agent header (set using `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/UrlRequest.Builder#addHeader(java.lang.String,java.lang.String)`) will override a value set using this function.

| Parameters |
|---|---|
| `https://developer.android.com/reference/java/lang/String.html userAgent` | the User-Agent string to use for all requests. |

| Returns |
|---|---|
| `https://developer.android.com/develop/connectivity/cronet/reference/org/chromium/net/CronetEngine.Builder` | the builder to facilitate chaining. |