参与的Java项目在本地能正常运行，但是到了服务器上，在使用到一个功能时报错，看后台日志，报了一个java.lang.NoSuchMethodError
Caused by: java.lang.NoSuchMethodError: org.bouncycastle.jcajce.provider.asymmetric.util.EC5Util.convertPoint(Lorg/bouncycastle/math/ec/ECCurve;Ljava/security/spec/ECPoint;)Lorg/bouncycastle/math/ec/ECPoint;在pom.xml文件中的确引入了这个包，版本是1.69。本地代码是存在报错中提到这个方法的，要不然编译也不会通过。
org.bouncycastle bcprov-jdk15on 1.69 为了查看服务器上org.bouncycastle.jcajce.provider.asymmetric.util.EC5Util这个类和我本地是否一样，需要用到反编译工具。反编译工具有很多，我这里使用了阿里开源的Arthas，这个使用方法比较简单。如果你的服务器上没有Arthas，可以参考官方文档进行安装，快速安装只需要两行命令
https://arthas.aliyun.com/doc/install-detail.htmlcurl -O https://arthas.aliyun.com/arthas-boot.jarjava -jar arthas-boot.jar启动时选择想要连接的进程。选择后执行jad反编译命令
jad org.bouncycastle.jcajce.provider.asymmetric.util.EC5Util然后就可以看到
ClassLoader: +-sun.misc.Launcher$ExtClassLoader@3e151de8 Location: /usr/lib/jvm/jdk8/jre/lib/ext/bcprov-jdk15on-1.60.jar /* * Decompiled with CFR. * * Could not load the following classes: * org.bouncycastle.asn1.ASN1ObjectIdentifier * org.bouncycastle.asn1.x9.ECNamedCurveTable * org.bouncycastle.asn1.x9.X962Parameters * org.bouncycastle.asn1.x9.X9ECParameters * org.bouncycastle.crypto.ec.CustomNamedCurves * org.bouncycastle.crypto.params.ECDomainParameters * org.bouncycastle.jcajce.provider.asymmetric.util.ECUtil * org.bouncycastle.jcajce.provider.config.ProviderConfiguration * org.bouncycastle.jce.provider.BouncyCastleProvider * org.bouncycastle.jce.spec.ECNamedCurveParameterSpec * org.bouncycastle.jce.spec.ECNamedCurveSpec * org.bouncycastle.jce.spec.ECParameterSpec * org.bouncycastle.math.ec.ECAlgorithms * org.bouncycastle.math.ec.ECCurve * org.bouncycastle.math.ec.ECCurve$F2m * org.bouncycastle.math.ec.ECCurve$Fp * org.bouncycastle.math.ec.ECPoint * org.bouncycastle.math.field.FiniteField * org.bouncycastle.math.field.Polynomial * org.bouncycastle.math.field.PolynomialExtensionField * org.bouncycastle.util.Arrays */package org.bouncycastle.jcajce.provider.asymmetric.util;import java.math.BigInteger;import java.security.spec.ECField;import java.security.spec.ECFieldF2m;import java.security.spec.ECFieldFp;import java.security.spec.ECParameterSpec;import java.security.spec.ECPoint;import java.security.spec.EllipticCurve;import java.util.Enumeration;import java.util.HashMap;import java.util.Map;import java.util.Set;import org.bouncycastle.asn1.ASN1ObjectIdentifier;import org.bouncycastle.asn1.x9.ECNamedCurveTable;import org.bouncycastle.asn1.x9.X962Parameters;import org.bouncycastle.asn1.x9.X9ECParameters;import org.bouncycastle.crypto.ec.CustomNamedCurves;import org.bouncycastle.crypto.params.ECDomainParameters;import org.bouncycastle.jcajce.provider.asymmetric.util.ECUtil;import org.bouncycastle.jcajce.provider.config.ProviderConfiguration;import org.bouncycastle.jce.provider.BouncyCastleProvider;import org.bouncycastle.jce.spec.ECNamedCurveParameterSpec;import org.bouncycastle.jce.spec.ECNamedCurveSpec;import org.bouncycastle.math.ec.ECAlgorithms;import org.bouncycastle.math.ec.ECCurve;import org.bouncycastle.math.field.FiniteField;import org.bouncycastle.math.field.Polynomial;import org.bouncycastle.math.field.PolynomialExtensionField;import org.bouncycastle.util.Arrays;public class EC5Util { private static Map customCurves; public static ECField convertField(FiniteField finiteField) { if (ECAlgorithms.isFpField((FiniteField)finiteField)) { return new ECFieldFp(finiteField.getCharacteristic()); } Polynomial polynomial = ((PolynomialExtensionField)finiteField).getMinimalPolynomial(); int[] nArray = polynomial.getExponentsPresent(); int[] nArray2 = Arrays.reverse((int[])Arrays.copyOfRange((int[])nArray, (int)1, (int)(nArray.length - 1))); return new ECFieldF2m(polynomial.getDegree(), nArray2); } public static ECParameterSpec convertToSpec(X9ECParameters x9ECParameters) { return new ECParameterSpec(EC5Util.convertCurve(x9ECParameters.getCurve(), null), EC5Util.convertPoint(x9ECParameters.getG()), x9ECParameters.getN(), x9ECParameters.getH().intValue()); } public static ECParameterSpec convertToSpec(X962Parameters x962Parameters, ECCurve eCCurve) { ECParameterSpec eCParameterSpec; if (x962Parameters.isNamedCurve()) { Map map; ASN1ObjectIdentifier aSN1ObjectIdentifier = (ASN1ObjectIdentifier)x962Parameters.getParameters(); X9ECParameters x9ECParameters = ECUtil.getNamedCurveByOid((ASN1ObjectIdentifier)aSN1ObjectIdentifier); if (x9ECParameters == null && !(map = BouncyCastleProvider.CONFIGURATION.getAdditionalECParameters()).isEmpty()) { x9ECParameters = (X9ECParameters)map.get(aSN1ObjectIdentifier); } EllipticCurve ellipticCurve = EC5Util.convertCurve(eCCurve, x9ECParameters.getSeed()); eCParameterSpec = new ECNamedCurveSpec(ECUtil.getCurveName((ASN1ObjectIdentifier)aSN1ObjectIdentifier), ellipticCurve, EC5Util.convertPoint(x9ECParameters.getG()), x9ECParameters.getN(), x9ECParameters.getH()); } else if (x962Parameters.isImplicitlyCA()) { eCParameterSpec = null; } else { X9ECParameters x9ECParameters = X9ECParameters.getInstance((Object)x962Parameters.getParameters()); EllipticCurve ellipticCurve = EC5Util.convertCurve(eCCurve, x9ECParameters.getSeed()); eCParameterSpec = x9ECParameters.getH() != null ? new ECParameterSpec(ellipticCurve, EC5Util.convertPoint(x9ECParameters.getG()), x9ECParameters.getN(), x9ECParameters.getH().intValue()) : new ECParameterSpec(ellipticCurve, EC5Util.convertPoint(x9ECParameters.getG()), x9ECParameters.getN(), 1); } return eCParameterSpec; } /* * Enabled force condition propagation * Lifted jumps to return sites */ public static ECCurve getCurve(ProviderConfiguration providerConfiguration, X962Parameters x962Parameters) { Set set = providerConfiguration.getAcceptableNamedCurves(); if (x962Parameters.isNamedCurve()) { X9ECParameters x9ECParameters; ASN1ObjectIdentifier aSN1ObjectIdentifier = ASN1ObjectIdentifier.getInstance((Object)x962Parameters.getParameters()); if (!set.isEmpty()) { if (!set.contains(aSN1ObjectIdentifier)) throw new IllegalStateException("named curve not acceptable"); } if ((x9ECParameters = ECUtil.getNamedCurveByOid((ASN1ObjectIdentifier)aSN1ObjectIdentifier)) != null) return x9ECParameters.getCurve(); x9ECParameters = (X9ECParameters)providerConfiguration.getAdditionalECParameters().get(aSN1ObjectIdentifier); return x9ECParameters.getCurve(); } if (x962Parameters.isImplicitlyCA()) { return providerConfiguration.getEcImplicitlyCa().getCurve(); } if (!set.isEmpty()) throw new IllegalStateException("encoded parameters not acceptable"); X9ECParameters x9ECParameters = X9ECParameters.getInstance((Object)x962Parameters.getParameters()); return x9ECParameters.getCurve(); } public static ECParameterSpec convertSpec(EllipticCurve ellipticCurve, org.bouncycastle.jce.spec.ECParameterSpec eCParameterSpec) { if (eCParameterSpec instanceof ECNamedCurveParameterSpec) { return new ECNamedCurveSpec(((ECNamedCurveParameterSpec)eCParameterSpec).getName(), ellipticCurve, EC5Util.convertPoint(eCParameterSpec.getG()), eCParameterSpec.getN(), eCParameterSpec.getH()); } return new ECParameterSpec(ellipticCurve, EC5Util.convertPoint(eCParameterSpec.getG()), eCParameterSpec.getN(), eCParameterSpec.getH().intValue()); } public static org.bouncycastle.jce.spec.ECParameterSpec convertSpec(ECParameterSpec eCParameterSpec, boolean bl) { ECCurve eCCurve = EC5Util.convertCurve(eCParameterSpec.getCurve()); return new org.bouncycastle.jce.spec.ECParameterSpec(eCCurve, EC5Util.convertPoint(eCCurve, eCParameterSpec.getGenerator(), bl), eCParameterSpec.getOrder(), BigInteger.valueOf(eCParameterSpec.getCofactor()), eCParameterSpec.getCurve().getSeed()); } public static ECDomainParameters getDomainParameters(ProviderConfiguration providerConfiguration, ECParameterSpec eCParameterSpec) { ECDomainParameters eCDomainParameters; if (eCParameterSpec == null) { org.bouncycastle.jce.spec.ECParameterSpec eCParameterSpec2 = providerConfiguration.getEcImplicitlyCa(); eCDomainParameters = new ECDomainParameters(eCParameterSpec2.getCurve(), eCParameterSpec2.getG(), eCParameterSpec2.getN(), eCParameterSpec2.getH(), eCParameterSpec2.getSeed()); } else { eCDomainParameters = ECUtil.getDomainParameters((ProviderConfiguration)providerConfiguration, (org.bouncycastle.jce.spec.ECParameterSpec)EC5Util.convertSpec(eCParameterSpec, false)); } return eCDomainParameters; } public static EllipticCurve convertCurve(ECCurve eCCurve, byte[] byArray) { ECField eCField = EC5Util.convertField(eCCurve.getField()); BigInteger bigInteger = eCCurve.getA().toBigInteger(); BigInteger bigInteger2 = eCCurve.getB().toBigInteger(); return new EllipticCurve(eCField, bigInteger, bigInteger2, null); } public static ECCurve convertCurve(EllipticCurve ellipticCurve) { ECField eCField = ellipticCurve.getField(); BigInteger bigInteger = ellipticCurve.getA(); BigInteger bigInteger2 = ellipticCurve.getB(); if (eCField instanceof ECFieldFp) { ECCurve.Fp fp = new ECCurve.Fp(((ECFieldFp)eCField).getP(), bigInteger, bigInteger2); if (customCurves.containsKey(fp)) { return (ECCurve)customCurves.get(fp); } return fp; } ECFieldF2m eCFieldF2m = (ECFieldF2m)eCField; int n = eCFieldF2m.getM(); int[] nArray = ECUtil.convertMidTerms((int[])eCFieldF2m.getMidTermsOfReductionPolynomial()); return new ECCurve.F2m(n, nArray[0], nArray[1], nArray[2], bigInteger, bigInteger2); } public static org.bouncycastle.math.ec.ECPoint convertPoint(ECParameterSpec eCParameterSpec, ECPoint eCPoint, boolean bl) { return EC5Util.convertPoint(EC5Util.convertCurve(eCParameterSpec.getCurve()), eCPoint, bl); } public static org.bouncycastle.math.ec.ECPoint convertPoint(ECCurve eCCurve, ECPoint eCPoint, boolean bl) { return eCCurve.createPoint(eCPoint.getAffineX(), eCPoint.getAffineY()); } public static ECPoint convertPoint(org.bouncycastle.math.ec.ECPoint eCPoint) { eCPoint = eCPoint.normalize(); return new ECPoint(eCPoint.getAffineXCoord().toBigInteger(), eCPoint.getAffineYCoord().toBigInteger()); } static { Object object; customCurves = new HashMap(); Enumeration enumeration = CustomNamedCurves.getNames(); while (enumeration.hasMoreElements()) { object = (String)enumeration.nextElement(); X9ECParameters x9ECParameters = ECNamedCurveTable.getByName((String)object); if (x9ECParameters == null) continue; customCurves.put(x9ECParameters.getCurve(), CustomNamedCurves.getByName((String)object).getCurve()); } object = CustomNamedCurves.getByName((String)"Curve25519"); customCurves.put(new ECCurve.Fp(object.getCurve().getField().getCharacteristic(), object.getCurve().getA().toBigInteger(), object.getCurve().getB().toBigInteger()), object.getCurve()); }}Affect(row-cnt:1) cost in 704 ms.通过靠前的Location:可以看到版本并非pom.xml依赖的1.69版本，实际使用的1.60版本，而且位置是jdk自带的jar包。查看这个类的内容，的确没有报错中那个方法（有方法名相同的，但是形参列表不同）。
到目前为止就找到原因了，是pom.xml引入了与jdk自带jar包同名的包，但是版本不一样。编译时使用了pom.xml引入的，但是在启动程序时，由于Java类加载的顺序，会优先加载jdk自带的类，导致运行时用的EC5Util这个类和编译时的版本不一样，缺少了一些方法，所以报了NoSuchMethodError异常。
解决方法：
我这里是把jdk自带的同名jar包bcprov-jdk15on-1.60.jar移动到了一个不相关的目录，然后重启程序。
当然也可以考虑修改代码，本地和服务器使用同样版本的jdk，使用jdk自带的jar包中的方法，不要从pom.xml中引入。